24 berths may not be in VIP quota, may be max 12-16 (6-8 per coach). & HO is not only for VIPs. It is used by normal people too incase of emergency. I used HO quota for clearance of my WL ticket in 12825 Jharkhand SK day before yesterday. I am no VIP, but I had to travel to appear for an exam, so I applied for it.
& In Patna Rajdhani in festive season, almost 80% HO is used, in chhath almost 100%.