If this were in Texas I would say that the language “more or less” means just that. If a company is going to form a legal production unit they are going to get a complete new survey of the unit. They can’t lease 10 acres from you and it is actually 12 and then pay you for the 10 Acre interest. There is a little more to this than that. Most likely the lease broker and landmen made a mistake and what you have is very valuable and they are going try to trick you and cover their mistakes.