Help deciding on interior paint for 20 unit apartment complex

[Tab Teehee]

I'm getting close to having the first 8 units of my 20 unit rehab ready for paint! I really would like some input from fellow BP'rs on this subject. Here are my thoughts.... Initially I was going satin or eggshell on walls but a former apartment maintenance guy, told me to forget about the need for washable paint! He said go with flat because it hides imperfections better and apartment walls don't get cleaned upon turns, they get painted and touch ups are easier with flat. I'm wanting to go with an off white like antique white, navajo white or something similar...ceilings are flat white and doors and trim semi-gloss white, so I want a bit of contrast for the walls. I was hoping to find pre mixed 5 gallons of something other than basic white, but so far haven't had any luck. Also not sure about brands and how important quality is? anyway I would love to hear from everyone on this! Thanks!