The Subs bid would not be irrevocable based on promissory estoppel; however, we could look to the Rest. 2nd 45, where in the comments it states that "part of a requested performance is given, the offeror will not revoke his offer,". If the court found that the offer was irrevocable, there would be no need for promissory estoppel, because the contract would be valid and enforceable. Here there are two different things. If the offer is irrevocable, then there is a valid contract.On the other hand if the court utilizes promissory estoppel,it is because there is no contract, and therefore, promissory estoppel is employed based on the other parties reliance.