Hello Chris,
price_quantity_start and price_quantity_end - it is only used to export prices. There are no such fields in general product exports.
You do not see those fields in VirtueMart Product export template?
Update available fields and check if you see those fields.
In general, I solved the problem in the above example of my XML template, but it's a bit strange that the selected price range in the product applies only to the product_price field
The calculation of other price fields is also based on the quantity. If there is no price_quantity_start field then quantity is set to default value 1. That should be the reason you are seeing random values in export.
If Virtuemart, using the same database, is able to calculate a discount from the selected range, then probably CSVI could do something like that too 
How and where does VirtueMart calculate discount for a range? As I mentioned earlier we do not calculate prices but RO CSVI uses VirtueMart files to calculate prices. So can you explain this in detail?
Kind regards,
Tharuna
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