Automatically hide/unhide rows based on cell value

Hello again,

As I have been playing with the file I noticed two things which I'm wondering if they could be adjusted.

1) the hide/unhide does not allow row 80 to unhide... it stops at 79.
2) when I try to protect each sheet (so people cannot mess with the formulas) there is an error and it cannot hide or unhide the protected rows.

Is there anything which can be done to solve these?

Please see the new reference file attached.

Thank you!