Your second sentence fits the requirement of sequence of tenses in a conditional sentence. However, the first form of the first sentence is very common. Perhaps someone else can explain why it is considered to be correct, if it is.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
AnonymousIf I hadn't spent so much money, I would be rich today.Correct. IF counterfactual situation in the past, (THEN) hypothetical result of that situation in the present.