Hi, If you skip repair in SC2018 stockcar after about 30 seconds (120 sec complete repair time) for avoiding being lapped, the next time pitting the repair time is still at 130 sec, so the first stop for repairing is useless.. I guess this makes no sense...
Unfortunately the damage model isn't nuanced enough to fit all scenarios. There's a lot of heavy damage that wouldn't make sense to do in parts, while other damage might work that way. At this point you need to do the damage repair all in one go. (there are still 2 scenarios where the skip option is useful: when you forgot to turn off minor damage repair, and where the car is in good enough condition to warrant getting back out in front of a safety car or similar and come back in for the repair in a lap or two. More major damage you just need to fix) Say you bend a steering arm and it's a 3 min job to replace it; you can't do that in halves and drive around (missing a front wheel!) in between. But better damage modeling to suit different car types would help immensely here.
