For calculating price differences, this should not happen if product type is "service". It should only happen for real products.
Thus particular code should be enhanced with smoething like
"if not product_type = service" then do price_diff calculation
Find an other small issue.
For calculating price differences, this should not happen if product type is "service". It should only happen for real products.
Thus particular code should be enhanced with smoething like
"if not product_type = service" then do price_diff calculation