Advance tax for casual taxable persons must be based on estimated net tax liability after available input tax credit. Advance deposit for registration as a casual taxable person must be calculated on the estimated net tax liability after accounting for eligible input tax credit. Long-running exhibitions exceeding the casual period require normal registration, use of allotment/consent letter as business proof, no advance tax for such registration, and surrender post-event. Excess credit improperly distributed by an Input Service Distributor is recoverable from recipients with interest and penalty; recipients may voluntarily repay using FORM GST DRC-03, otherwise recovery proceedings under the statute using FORM GST DRC-07 may be initiated and the ISD faces a general penalty.