It seems one of the worst problems with any migration from 1->2 is the default "Discount Type".
It seems to default to 0 = "Apply Generic Rules."
Bad idea (IMHO). This seems to create a "default" chaos with the shop opening where there appear any number of unintended Discounts on the shop that can cost some serious money loss.
Our solution is to apply this MySQL command on all web-shops we migrate...
QuoteUPDATE JOOMLA-PREFIX_virtuemart_product_prices SET product_discount_id = '43'
This command changes all "Discount Type" values to 43 which = "Apply no rule."
PS. Change the
JOOMLA-PREFIX_ to suit your site prefix.