SmartList Excel imports changed with GP 2013. They got a lot faster, but lost their formatting. Debit and Credit amounts come out with 5 decimal places. A lot of people have reported this as a bug. It’s not, it’s a design choice.
I looked at this last week and want to mention that the old, unsupported dex.ini switch still works.
If you add:
SmartlistEnhancedExcelExport=True
to the Dex.ini file you get faster imports and some formatting.
Keep in mind that this switch is still unsupported. If you have problems with the results you won’t get any help, but it is an interesting option.