The Mega has a steep seat tube – bear this in mind when looking at the geometry.
Basically, standing the seat tube up moves the seat cluster and top tube forward from the bottom bracket by about 10mm per degree. The Mega is 75 degrees, 2-3 steeper than common.
The effect is that the bike has a longer reach (bb to head tube) than the top tube number implies. Roughly 30mm more than other bikes I looked at. Therefore it feels longer when stood.
Saying that, it’s not a big bike, 6 foot and my large feels short when seated – but long and stable when stood and ragging it, which is how it should be ridden.
Don’t know if that helps.