Excel Expert for average formula issue

Hi I'm trying to find an average that updates weekly based on input in specific columns and an allotted amount of hours. The average should be equivalent across all 13 weeks when started. (This will be replicated 4x once for each quarter). Once hours are inputted into ANY Week's USED column, the average availability columns without any hours inputted into the used columns, is updated accordingly based on remaining weeks and remaining total hours. For Example If Allotted hours for the quarter is 1300, week 1 uses 100 hours, then the hours should still be 100 for the next 12 weeks. However if you put in a 0 or any other # into used hours for weeks 2-13, the average available will get updated to show an updated # for each week. I tried some formulas attached but nothing was coming out correctly to even start me off. Thanks