Presently we use the following formula and it works great:
=IF(COUNTIF(D4:AB4,">0")<3,C4,IF((((SUM(D4:AB4)-(COUNTIF(D4:AB4,">0")*36))/COUNTIF(D4:AB4,">0")))*0.9>20,20,(((SUM(D4:AB4)-(COUNTIF(D4:AB4,">0")*36))/COUNTIF(D4:AB4,">0")))*0.9))
What is says is you must golf at least 3 times before the formula will recalculate a new handicap otherwise you are stuck with (C4) what you started with and we only use 90% of your average to compute your handicap.
However after many weeks of play ones handicap hardly changes due to the vast amount of entries; to keep the handicap current we want it to to use the 5 most current scores and yet do all the rest the formula presently does.
Because people miss or are absent there will no postings in some weeks so then we want it skip the blanks and just use the posted weeks