When tracking total capacity usage, the game does not round the capacity requirements of each component to an integer when determining whether or not components will fit; if you have 9 components which each take up 5.6 capacity, they will consume 50.4 capacity on the ship. The ship design screen will round the value off to an integer when it tells you how much capacity you've used up, but it will not use the rounded value when determining whether or not additional components will fit, which is extremely irritating, and has become even more so now that they've changed the component capacity requirements in a way that makes it considerably more likely for fractional capacity values to show up, including fractional values below the tenths place. If your ship actually uses x capacity, where 124.4 < x < 124.5, the game will display x as 124 but a component which actually requires 5.6 capacity will not be able to fit on a hull whose maximum capacity is 130, because for x > 124.4, x + 5.6 > 130.
