Max/Min formula

Hi All,

First time poster. I am hoping someone may be able to tell why this max/min formula returns no value when entering negative criteria? The aim of the formula is to take an annual value, and aportion across 12 periods on a 4week, 4week, 5week basis, until an end date is reached within the criteria. So I would like row 10 on the example, to show a negative value from column Q onwards, until the end date show in column L.