ABCDEFGHIJKLMNOPQRSTUVWXYZAAABACADAE
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novdecjan-13febmarchaprmayjunjulagustseptoktnovdecjan-14febmarchaprmayjunjulagustseptokt$169.00
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3030302520201400000000000000000$169.00
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33302220000000000000000010
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1$10.00$10.00$10.00$5.00$35.000.02Column a is the subscribers and row 1 is the months

The monthly charge is $10 but sometimes people pay whatever amount suits them so if someone pays $35 I may add $10 for three months and $5 for one and then the end column (z) adds it all up.

I feel this is error prone and could be easier so is there anyway I could just add the newest payment to the sum column(s) and that total amount automatically divided in the month columns and populate them? Note no month should have more than $10. So in the the example above I would add $35 and sheets would fill in these 4 columns (b, c, d ($10 in all) and e ($5)) and if I would later add $25 it would complete column e and f


Also I was thinking is it possible for sheets to either add a comment or update a comment with the current date when a particular cell is edited? I would like it to add a comment to column when that cell is edited
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2$10.00$10.00$10.00$10.00$10.00$10.00$5.00$65.000.04
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3$10.00$10.00$10.00$10.00$10.00$10.00$9.00$69.000.05
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4$0.000.00
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5$0.000.00
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6$0.000.00
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7$0.000.00
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8$0.000.00
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9$0.000.00
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10$0.000.00
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$0.000.00
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$0.000.00
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$0.000.00
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$0.000.00
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$0.000.00
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$0.000.00
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$30.00$30.00$30.00$25.00$20.00$20.00$14.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$0.00$169.000.11
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3333222000000000000000001010.00
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