Limitation exclusion for stayed proceedings preserves computation periods and maintains enforceability of tax, interest and recovery obligations. Periods of stay or appellate litigation are excluded from computation of limitation for tax determination; if enhanced-charge notices requiring proof of fraud are held unsustainable, tax shall be determined under standard provisions. Orders directed by appellate bodies must be issued within two years. Procedural safeguards include a right to hearing on written request, limited adjournments, reasoned orders, prohibition on demands beyond notice grounds, automatic interest on short-paid tax, adjustment of interest and penalty following appellate modification, recovery of unpaid self-assessed tax under recovery provisions, and prohibition on duplicate penalties for the same act.