Some tanks, especially squat/cube ones like this and my Aqua One 620T, do tend to give confusing water volume readings. My 620T is ~62lx39wx70h cm including the hood for the lighting and wet/dry filter, but can only be filled to ~55cm, giving ~130l.
A lot of manufacturers these days seem to quote the volume as the space inside the glass walls rather than the water it will hold. I can only assume they think it makes the tank sound better value for money.
I have one tank which has a plastic trim round the vertical corners - the quoted volume includes that as well, they are including a layer of air round the outside of the tank!
In that case, the website is quoting the volume of water it will hold, though some will be displaced by the substrate, decor etc. The height measurement they give will be the height of the glass, which will include some air space on top of the water and might even include the hood if it sticks up higher than the top of the glass.
It is always better to go with the true volume and not the measurements that give the bigger result in the calculator on here, especially if the height includes the air space above the water and possibly even the hood. If you use the total height measurement instead of the water height measurement to give a bigger volume in the calculator that will only make stocking issues even worse.