I've got an array formula to add a column of numbers, some with one decimal place. The complex part is that the decimal isn't 1/10th, it's 1/6th. Cricket overs count 0.1, 0.2, 0.3, 0.4, 0.5, 1.0... and so on. So 0.3 + 0.3 = 1.0

=SUM(INT(J5:J24))+INT(SUM(MOD(J5:J24,1))*10/6)+(MOD(SUM(MOD(J5:J24,1)*10/6),1))*6/10

I have just noticed that sometimes, if the first two numbers both have a point three (eg. 5.3 and 6.3) it shows 11.6 instead of 12. It works every other time.

Anyone have any idea why this happens or how to fix?
Thanks