If you were at 297 then added 2 levels and are still at 297, then there is definitely a problem. I have a spreadsheet that calculates my kingdom power from my troop/trait/level count and it is always a perfect match (at least since I got my formulas working right). Even with that, I still got caught by surprise when I thought Blighted Lands was SO CLOSE to 7* that I should be able to do it, but couldn't quite squeeze out enough points with the diminishing returns.
They put the formulas in that way so that as the number of troops in each kingdom increases, it won't be too easy to reach 5* for newer players. After the equivalent of 10 maxed out troops, the points are much more costly to acquire.