Who determines the contest start time ? The writer(s) or Mike Mirzayanov?

if you take a look at upcoming contests, You will notice that 3 unusual start times are there.

this unusual start time happened in some of recent contests too. I am familiar with 14:35 UTC start time ( I think 54 out of 56 contests I participated, started at that time, and that 2 contests started at 10:35 UTC I think, which both were on Friday ).