my interpretation of that guide page is that a medium shield will have better absorption ratio when equipped on the same mech/bot as a small shield.

The thing is that it doesn't happen like that when I test it... I tried small and medium shields on troiar, waspish, tyrannos and ictus... always same absorption rate for a given bot/mech.

of course I only looked at the reported absorption when you click the information option on the equipped module (after deploying, not on equip screen), I didn't do any combat testing yet... could it be that the reported abs. ratio is bugged?