Student or Learner
"If you order the same amount of goods, we are going to roll back the price by five percent." Is it correct to use "roll back" meaning to reduce the price?
Wal Mart advertises in the US that they continually are "rolling back" their prices.
The term "roll back" implies that the prices were lower in the past, and they are rolling back to the prices to when things where cheaper. I wouldn't use it in your context.
Try: We will discount the price by 5%. We will offer you a 5% discount.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.