proper fluid level on 727TF

i just don't understand why someone would run a deep trans pan and not put the filter spacer on...

had know idea that should be done in conjunction with deep pan? my thought was more fluid dont run dry like oil pan? next time i got pan off a spacer is going in. with all this being said ,whats a safe fluid level on a stock filter location? even with gasket boss, or even with dipstick tube mounting boss?