Even at 12.5v cutoff, you aren't losing very much runtime at all; probably like 30 seconds if that. Lipos drop off rather quickly towards the end, which is why most people actually prefer a slightly higher cutoff. 12.5 @ 4s is 3.125v/cell, which is just about perfect IMO. And a higher cutoff is better for the pack...
Does anyone use another LVC? One that can be programmed?
Yes, the difference may be 30 seconds, but 30 seconds is a lap. I have my Mamba Max set at 11.8v in my 1/8 buggy. You can discharge LiPo to 2.7v per cell without doing damage.