Timesheet Formula - Time in Lieu

Please refer attached timesheet.

I am trying to add IF statement to the current formula both Column H8..H12 and I8..I12, this would calculate minus the normal total hours which is 7.6 (in decimal), if the worker either starts or finishes early than normal time (see D3 & D4). The current formula I already add in H8 to H12 and I8 to I12 which is correct but I need to add IF statement to minus the hours from normal hours per day in decimal (see cell h4).

I hope you know what I mean as it is hard to explain in English. For your information, I have typed the results in cell B14 to B16 which the value should shown in cell G10 to G12.

Much appreciated for your assistance.

Thanks.