The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( Trefis) -- Groupon ( GRPN) recently restated its fourth-quarter 2011 earnings, which resulted in lower revenue and net profit because of an increase in Groupon's refund reserve accrual. This was due to a shift in the company's deal mix which now includes higher priced deals which generally have higher refund. Since the refund rates are generally much higher for such deals, Groupon had to increase its refund reserves, and this led to a decline in reported sales and an increase in operating expenses. It has already been hit with an SEC probe and a shareholder lawsuit following the restatement. However, that won't be the first lawsuit it will have to deal with. It is already fighting a series of lawsuits related to illegal coupon expiration dates for its coupons.