Charitable trust-accounting

If the charitable trust is established wholly & exclusively for the purpose of charity & not even a single part of its activity is carried on for business purposes then the AS's are N/a to the charitable trust.  However if it proved that even if a single objects of the trust are carried on for business then the AS's would ebcome applicable.

Trust's income is exempt from the payment of I-T, so there is no need of making provision for tax.  Depreciation shud be charged to P&L at the rates specified as per the I-T Act.

Exclusive Trust (100% for charity)- If none of the AS are applicable on it then what are the rules for accounting in trust.

Non exclusive Trust - As per the trust definition an entity has to invest 85% of the income into charitable purpose to maintain the charitable trust status. Which means 15% of the income can be invested into other business purpose. In that case will that trust be considered under non exclusive trust ( all AS applicable) or not?