From reading most post it sounds like the reason for not using computer mode and using gauge mode is to allow you to get out of the water faster. But it is not going to hurt you to hang alittle longer at your 10 ft stop.
To answer the question about BT or computers, I have a DR Duo and OMS BT. I plan my dives with V-planner. I just dove FRI-SUN did about 8 dives in the 145ft-115ft range and my computer and vplanner were pretty close together. The computer would have me stay maybe an extra couple of minutes at 10ft but it can only help not hurt.
Note the Sit times are put before the dive but they are the sit times between dives.
Here is my profile from the trip:
SI: 03:00 Profile: (140, 25, 21) Deco: 71,
SI: 05:00 Profile: (145, 25, 24) Deco: 75,
SI: 11:45 Profile: (115, 25, 28) Deco:
SI: 02:30 Profile: (115, 35, 29) Deco:
SI: 02:30 Profile: (115, 30, 30) Deco:
SI: 02:00 Profile: (115, 40, 30) Deco:
SI: 11:30 Profile: (115, 30, 31) Deco:
SI: 24:00 Profile: (115, 40, 31) Deco: