So, I noticed that ships put in hangars get their armor repaired by the mothership, but not at a consistent rate. Ships that are docked at the same time aren't repaired at the same time. If it's a set number of armor hexes repaired per tick, I haven't a clue how large the ticks are or what the rates are.
In general, I've been unable to find formulas for how damage control repair speed is calculated, and I would be interested to know if someone else has already done the testing before I do further experiments.