If you want written proof that AICTE allows you to stay outside the hostel also then go to the notification released by AICTE for PMSSS. In the pdf, it is mentioned for the students will get the maintenance charges in their account directly which means they can give that, to the college if they are staying in the college hostel and the flat/PG owner if they are staying outside the college, but they have to upload the proof of the same.
Though if your college is not allowing you to stay outside college then ACITE, PMSSS has no role to play here and these are the policies by your college in which you have taken admission.
If they are not allowing any student in their college to stay outside the hostel then PMSSS students cannot ask for a unique treatment.
Though if they are asking for more than 1 lakh hostel fees then you can tell them that we only get 1 lakh for hostel and maintenance fees and you can mail to AICTE regarding this.
Hope this answers your query