................

if you create a blank row as row 7
so 8 is 01-apr-21
i8=IF(G8>19,MIN(8000,H8)*$I$6-SUM($I$7:I7),0)
j8=IF(AND(H8>8000,G8>19),MIN(8000,H8-8000)*$J$6-SUM(J$7:J7),0)
k8=IF(AND(H8>16000,G8>19),MIN(16000,$H8-16000)*$K$6-SUM(K$7:K7),0)

if you had put the km limits in cells they would not need to be hard coded and the formula could have been copied across