hi, Jeff !

... protected sheet with a range of unlocked cells.
... disable the delete and cut operations on these cells?
... still like to be able to use clear contents and copy and paste

[i think that...] - 'disable the delete and cut' ...
[it is 'against'] - 'still be able to use clear contents' -?-

[i guess that] you might want give a try...
- change your time time entry 'sum' formulae to [something like]...
=(((Row10)*(Row2-Row1))+((Row30)*(Row4-Row3))+((Row50)*(Row6-Row5)))*24

hth,
hector.