(petitioners, married couple, not entitled to greater casualty loss deduction for tornado damage to home than what IRS allowed due to lack of substantiation; petitioners received insurance reimbursements of $37,524 and paid contractors $27,353 for cleanup and repairs; $40,355 casualty loss claimed on joint return and husband's business claimed casualty loss deduction of $7,121 for residence on Form 1065 attributable to office in home; petitioners attempted to calculate before and after value of home and subtract insurance proceeds and estimate of damage caused by tornado; subsequently hired appraiser producer report with numerous valuation errors; all property and casualty loss involved personal assets; cost of actual repairs must be substantiated if repair costs to be used in valuing loss rather than estimates; petitioner hypothesized values and amount of loss; accuracy-related penalty imposed).