Also bear in mind there are complex multi-engine aeroplanes covered by a Type Rating which under 61.061 meet the flight review requirements for the multi-engine aeroplane class rating. Eg. King Air 350, Beech 1900, Dornier 228, G-73 Mallard, Merlin/Metro variants.
So a Flight Review in any of the above type rated aircraft would keep your multi-engine aeroplane flight review current which automatically in turn would cover your single-engine aeroplane flight review requirement.