Use 'Center Across Selection' instead of 'Merge and Center'
I have been using Merge and Center for as long as I've known Microsoft Excel (many years!). Most of the time, it is the perfect solution to merging and centering data. Sometimes, however, it does become a bit troublesome especially when it comes to sorting and filtering text or moving cells around.
A better way is to use 'Center Across Selection' instead. Select the cells you want to "merge". Click the call-out on the Alignment group. In the drop-down options underneath 'Horizontal', select 'Center Across Selection'.