Autodesk fusion 360 gears
You see the distance between the "pitch line" of the tooth and the tip is equal to the module (in your case 1mm) and the distance between the "pitch line" of the tooth and the bottom is 1.25*module. If "h" refers to the tooth height, then no, "h/2" is not the right equation to use.
I don´t know if your h/2 refers to the tooth height or the rack height so I´m going to tackle them both if "h" refers to the rack´s height it's simple common math knowledge that if you change that height your equation will simply not work. Yeah the thing is that you´re using the wrong equation to line them up. This design method is still in development and should not be relied on for accurate visualization or industrial level designing. If you’re planning to fabricate these gears using our designs, you have to consider they won’t reflect the “under cut” condition (for more information, visit KHK Profile Shifting). Profile shifting is a manufacturing method for gears that are needed to fit a larger/smaller mesh space while remaining with the same specs (number of teeth, module, pressure angle, etc.). The two variants considered experimental are the ones that use profile shifting. Nonetheless, these designs are as useful as others. The two types considered non-standard were included for 3D printing since these designs of internal gears have proven to be practical when tight tolerances are a liability.
Regardless, it is made for everyone, no matter your amount of knowledge or if you have an engineering background. As such, its designs are made following the metric module DIN standard series. This is a minimalistic gear design application.