If Host Tools is showing a different price than you expected for a date, there is an easy way to see how Host Tools got that price.
If you click on one of the dates that looks off, a pop-up on the right will appear. This shows how Host Tools chose the price it has.
Some common issues are that you have a minimum price set and are trying to set your price lower than your minimum, or that you have your pricing rules applied in the wrong order.