Errata ....

I wrote:
E18: =MIN(50,I19/5)

That should be =MIN(50,ROUND(I19/5,0))

E8: =ROUND((I19-E18)/4,0)
E9: =ROUND((I19-E18-E8)/3,0)
E10: =ROUND((I19-E18-E8-E9)/2,0)
E16: =I19-E18-E8-E9-E10

I probably misinterpreted what your E-cells represent.
These formulas probably belong elsewhere. But
hopefully the idea is clear.
..