Why delaying Stutterwarp Discharge is rare

Introduction

There are several reasons why delaying drive/coil discharge is rare ( something only the stereotypically "crazy" PCs would risk trying).

The 24 Hour Countdown to Doom

If a starship has "tuned" its drive when discharging ( the task on DG p63), then it can attempt to exceed the 7.7 LY range, for just 24 hours.  Once it goes past 7.7 LY, the 24 hour clock starts ticking.

When that time is up, if it is not currently discharging the hyper-saturated drive coils, then the crew dies ( when the drive breaks down and irradiates the entire ship).

If your starship's stutterwarp drive, powerplant or computer system malfunctions during this 24 hour countdown, then you may not make it to the nearest gravity well sufficient for discharge if the repairs take too long.

The destination's "terrain" matters

The starship really needs to know a lot about its destination.  Every hour spent flying "in system" ( inside your destination's FTL Threshold) or in orbital gravity-drop ( thruster-free) maneuvers trying to get into a planet's discharge orbit reduces the time you actually have ( out of 24 hours) to fly at FTL speed ( between systems).

Here are two examples ( and the assumptions behind them) showing how little extra LY distance is gained ( beyond 7.7 LY) given:
1) the time lost in the destination system ( while getting to/into a discharge orbit within the 24 hour time limit)
2) and the starship's speed ( WE).

Trying to make it to the Sol system

Note: 
  WE = Stutter Warp Efficiency
  Extra LY = The extra distance in LY beyond 7.7 LY

ASSUMPTIONS
  0.645 Insystem constant
  1.45  Shortest Path from Sol's FTL threshold to Earth
  6     Hours needed to match orbital velocity

TO OUTER GAS GIANT            TO EARTH 
OUTSIDE FTL THRESHOLD         INSIDE FTL THRESHOLD

  Extra LY   WE required        Extra LY   WE required
  0.0        0.00               0.0        3.00
  0.1        0.13               0.1        3.13
  0.2        0.27               0.2        3.26
  0.3        0.40               0.3        3.40
  0.4        0.53               0.4        3.53
  0.5        0.67               0.5        3.66
  0.6        0.80               0.6        3.80
  0.7        0.93               0.7        3.93
  0.8        1.07               0.8        4.06
  0.9        1.20               0.9        4.20
  1.0        1.33               1.0        4.33
  2.0        2.67               1.1        4.46
  3.0        4.00               1.2        4.60
  4.0        5.33               1.3        4.73
  5.0        6.67               1.4        4.86
                                1.5        5.00
                                1.6        5.13
                                1.7        5.26
                                1.8        5.40
                                1.9        5.53
                                2.0        5.66

Trying to make it to a typical French Arm colony system

ASSUMPTIONS
  0.645 Insystem constant
  1.38  Avg Shortest Path from FTL to colony world
  6     Hours needed to match orbital velocity

TO OUTER GAS GIANT            TO INNER COLONY WORLD
OUTSIDE FTL THRESHOLD         INSIDE FTL THRESHOLD

  Extra LY   WE required        Extra LY   WE required
  0.0        0.00               0.0        2.85
  0.1        0.13               0.1        2.99
  0.2        0.27               0.2        3.12
  0.3        0.40               0.3        3.25
  0.4        0.53               0.4        3.39
  0.5        0.67               0.5        3.52
  0.6        0.80               0.6        3.65
  0.7        0.93               0.7        3.79
  0.8        1.07               0.8        3.92
  0.9        1.20               0.9        4.05
  1.0        1.33               1.0        4.19
  2.0        2.67               1.1        4.32
  3.0        4.00               1.2        4.45
  4.0        5.33               1.3        4.59
  5.0        6.67               1.4        4.72
                                1.5        4.85
                                1.6        4.99
                                1.7        5.12
                                1.8        5.25
                                1.9        5.39
                                2.0        5.52

If you want to try these calculations with different assumptions ( insystem speed constant, range to planet, etc), then you can try this javascript calculator.

Note: it requires your browser to have javascript activated/on.

Oops -- You might break the Stutterwarp Drive

While the task in the DG is not uncertain, it still is risky.  Under 2300's task system there is a flat 10% chance of the task failing, and a smaller one that the attempt to "fine tune" the discharge will break something.  The skill of the engineer does not affect these odds.

If a ship routinely tries to delay discharge every time it makes a flight ( or even more than a handful of times a year), there is an ever increasing chance that "Minor" or "Major" damage will be done to the drive ( rendering it inoperable -- see DG p 43).

Here are the cumulative odds based on the number of times the task is attempted:

       Super     Minor+    Major
       ficial+
  0     0.00%     0.00%     0.00%
  1     0.83%     0.49%     0.07%
  2     1.66%     0.97%     0.14%
  3     2.48%     1.45%     0.21%
  4     3.29%     1.93%     0.28%
  5     4.10%     2.41%     0.35%
  6     4.90%     2.88%     0.42%
  7     5.69%     3.35%     0.49%
  8     6.48%     3.82%     0.55%
  9     7.25%     4.29%     0.62%
 10     8.03%     4.76%     0.69%
 11     8.79%     5.22%     0.76%
 12     9.55%     5.68%     0.83%
 13    10.31%     6.14%     0.90%
 14    11.06%     6.59%     0.97%
 15    11.80%     7.05%     1.04%
 16    12.53%     7.50%     1.11%
 17    13.26%     7.95%     1.17%
 18    13.98%     8.40%     1.24%
 19    14.70%     8.84%     1.31%
 20    15.41%     9.29%     1.38%
 25    18.88%    11.47%     1.72%
 30    22.20%    13.60%     2.06%
 35    25.39%    15.68%     2.40%
 40    28.45%    17.71%     2.74%
 45    31.38%    19.69%     3.08%
 50    34.19%    21.62%     3.41%
 55    36.89%    23.51%     3.75%
 60    39.47%    25.35%     4.08%
120    63.37%    44.28%     8.00%
180    77.83%    58.40%    11.75%
240    86.58%    68.95%    15.36%

Conclusion

Given all of this, and the fact that starships are valuable ( and cannot afford the time lost with unneeded breakdowns), you will not see civilian starships attempting this maneuver, as the risk is too high.

Even major military starships ( especially those carrying smaller stutterwarp equipped missiles/lander -- which would each need to have this task applied successfully to them too before the voyage can start) will avoid it.

It will mainly be a risky maneuver attempted by truly desperate starships, like a military courier ship with urgent news, or PCs in their private ship ( in the usual trouble PCs get into).