SC question...

I put in an "If Needed" YS with prefences for SC times during the day and was instead given a SC from 2359-0859. How do I determine if CS followed the YS? I read the SRH where it says preferences will be considered in seniority order but do I just need to go looking through the Res Avail List and see who got what SCs to see if senior pilots got the daytime SCs?

Also does anyone know why these middle of the night SCs start at 2359 instead of on the hour? Is there some advantage for CS to have it technically in two days? TIA