Build custom travel time/distance matrix tool for large batches of distance-pairs, using the Google Maps/Google Earth services (Distance Matrix API)

We are looking to build a custom travel time/distance matrix tool that will collect, error-check and process large batches of distance-pairs using the Google Maps/Google Earth services (Distance Matrix API), and returning/populating the data in a user-friendly format such as an Excel file. Our batch sizes can be large - perhaps up to one hundred thousand pairs in a batch. We understand this would require us to have a Google Premium Plan, which will charge for each location pair request. Accordingly, we need to ensure that functionality is robust, so we don’t have mid-process failures, erroneous data loads, etc. that would trigger unnecessary requests and charges. The location pairs may be lat/lon coordinates or place names. If possible, we need to a check on international place names actually used as the Google “guess” sometimes is not accurate for unknown places. Ideally the tool would operate in and draw the necessary location pair information from a spreadsheet in MS Excel for Mac (2011 or 2016), and either update cells in that sheet or generate a new Excel sheet with the returned data. A sample setup spreadsheet is provided for illustrative purposes. As an option, we would also entertain a user interface in Google Maps or Google Earth that allows a user to load a large database of locations, select an origin, then select a group (e.g. radius or polygon) of destination points and process all the distance pairs, exporting to an Excel friendly format. We are open to your thoughts and suggestions about the best approach to meet our needs.