400k for A319 is too low, since mx cost for some older A319 will be 1,5 - 2,1 with leasing price 400k its giving 900k - 1,7m loss.
There is limit 5 % from the a/c price as minimal leasing price, but i think it should be at least 10 %.
From broker view is 10 % minimal since broker has not routes to feed with thems his funds.