It appears the AES has a 25mm balltop according to this guy, but the threading is the same based on what these other dudes are saying. May be where the confusion came in. I don’t know that you got a wrong part though, as an LB-30 should look bigger than an AES balltop if it really is 25mm.
Did you (consciously) order the Seimitsu LB-30 Solid Black Ball Top thinking it’d be the same size as your AES balltop?
Because it sounds like that’s the case, and that’s more of you having ordered the wrong part rather than PAS having sent you the wrong part…
You’re right to doubt what dubious websites claim. The ** original AES “crack prone” purplish hue balltop is 30mm diameter**, I measured it myself with a caliper . Perhaps there is a confusion on various websites between the original AES stick and the later bean shaped one with that weird looking top that’s part bat top, part ball, like those seen on industrial joysticks (video-audio mixing) and early computer sticks, anyways the link you provided (neogeo forums ) as source for the info is either edited or not the right one, since there is no mention of 25mm. Only the dude on shoryuken states it is “25mm”. Perhaps he alone mixed things up.