40% is the limit set to avail PWD quota under Visual disability clause under Persons with Disabilites Act. And PWD is not a vertical reservation. It is a horizontal reservation within your Category. For example, lets say you belong to OBC Catgeory with 40% Disability, you qualify under OBC-PWD Category. But if a Candidate belongs to SC Category and has more than 40% disability, then he/she doesnt qualify for PWD reservation. But only qualifies for SC reservation. Should that Candidate get a seat in NEET, he/she can take admission under SC Category and not under PWD Quota.