So as an experiment, I tool the "Blink" example and exactly doubled the size of the sketch by adding "ledPin2" that gets the same things done to it as ledPin. This cause the sketch (compiled with the arduino environment on Mac) to increase in size from 1414 bytes to 1470 bytes (56 bytes)
(With the patched 14, it when from 954 to 1010 bytes; same increase!)
(with version 11, which has a compiler that is "well known" to produce smaller code, the change was from 1092 to 1148; same increase, so this is apparently not the sort of code whose size changed!)