Again, thanks for your help. Looks like the LL will win out. If we challenge his double-charging us for a/c from Nov. to April -- DCHR could tack on an additional sum of money to our rent which will stay as part of our rent for lease renewals, etc., and then come June, LL can start charging us the Rent Stabilization charges of $19+ per air conditioner per month on top of the raise that we may get for the initial challenge of double-charges. Seems fruitless to fight the double-charges and end up just getting our rent raised -- and in June the LL will start charging the $19+ per a/c per month anyway.
I again thank you.