Exclusion of stay periods pauses limitation for tax determination; hearing rights, limited adjournments, adjusted interest and recovery apply. Periods during which service of notice or issuance of order is stayed are excluded from limitation for tax determination; appellate findings that fraud or willful evasion charges are untenable require the proper officer to determine tax under ordinary assessment procedure, and directions from appellate bodies must be implemented within a two year period. Procedural rights include written-requested hearings, limited adjournments, recorded reasons in orders, prohibition on demands exceeding notice grounds, automatic interest on unpaid tax, modification of interest and penalty upon appellate adjustment, recovery of unpaid self assessed tax under recovery provisions, and a prohibition on imposing multiple penalties for the same act.