Yes you can do that. Before deleting all records make sure that you have a back-up of your site to restore to if needed.
There are a few ways to handle this, under Import there is a Skip geocoding, update duplicates , etc etc.. You would want to select skip geocoding if you have the lat/long in the export files. That will speed up the import process and not add to any query limitations.. (all the Google query limits are changing, see news feeds and posts and documentation about the changes such as adding a billing account if you haven’t done that as yet. If you are running SLP version 4.9.15, you will notice there are two fields if you decide you want to restrict the HTTP referrer please read the info about that as well.)
https://docs.storelocatorplus.com/blog/location-imports-with-power-add-on/
If you do decide to do a fresh import make sure the file column called sl_id is deleted if you are deleting all locations and adding as a fresh install. sl_id is the id that the SLP locations database assigns. If you do NOT delete your locations the sl_id must match what is already in your locations table.
See the CSV duplicate handling