Anyone selling is responsible for giving a description of the record.Wether visual or play grade.Visual only doesnt mean much cos it could play like a bar-b-cue.Selling from visual only (unless for cheap stuff,take your chances,) is just idleness.
Marrying visual and play plus adding in marks,wol,edge warp,ringwear,gives confidence to the buyer,who may then repeat buy.
On the subject of EX,to me that means played,but has had no effect on the visual or play value.
Because its not a real science chaps.Adding + or - to grades,is in the ear and eye of the seller.
VG,VG+,EX,M-,M.
M grade i'd expect it to suck the static dust off as you draw it from the company sleeve.