Not really, it depends in memory alignment options and also in optimization options, so the size can indeed vary as I've saw it happening in many different cases, not exactly this one, but just saying it's not something static for sure.
I have already been in several places that use the same function, I went where it makes the effect of the angel, I went in the satan, horse, between several places where the struct is used I tried to change the 0xC and did not change the size of the item no time, Maybe the main has only 1 place to do this, even in the own makepreview I've tried.