I agree with the previous posters, what led you to believe that if you book and agree and all in price of 198, and leave early that you will pay only 99.
Did anyone in the hotel say this or was it listed on their website ?
Go for the 2 x B&B plus one evening meal for €99. Have the evening meal on the first night. Then due to unexpected circumstances say that you cannot stay the second night. I don't see a problem with this. Pay by cash.