'90s Thermal Racerback Tank

This brand is consistently off on the sizing. I've had issues with every single item I've purchased from Good American, it's either too small or too big. This tank top fits fine everywhere except at the bottom hem, where it is too tight and has no give. This is similar to the other items I've purchased that are too small--they fit almost everywhere, but have one area that is stiff and small. I suspect they do not attempt to fit multiple body shapes, size inclusivity proclamations are not the same as actually making items to fit different types of bodies. Using my current measurements, which indicate a 4 in their bizarre sizing system (why do they have their own system, btw? This may be an attempt to address the problem of size flux that women's clothes struggle with where you're a 12 in one brand, a 14 in another, and a 10 in a third, but it's not really a fix), I gambled one last time. At least it was only $10.