Macro(VBA) works too much slowly in excel 2013

I was protecting the sheet for restricting the user to change the cell that are not allowed.

I could not find the solution but I changed my logic of protecting like:
MySheet.Protect userinterfaceonly:=True Password:=SHEET_PASSWORD

I protect the sheet only once when file opens, This allows me to change the cell content by VBA(Macro) but dont allow user to change.

Now I only change the Locked property of cell for changing the permission to user.

This works faster but not compared to Excel 2003.

Still looking for better solution.

Exact same issue here. Was a solution ever found? Does anyone else know of a solution? Not much info online about Excel 2013. Thanks