Chalcone synthase that can also use isovaleryl-CoA, isobutyryl-CoA or hexanoyl-CoA as substrates, but that is unable produce olivetol or olivetolic acid. 4-coumaroyl-CoA + 2 H(+) + 3 malonyl-CoA = 2',4,4',6'-tetrahydroxychalcone + 3 CO2 + 4 CoA Expressed in glandular trichomes. Detected at low levels in female flowers, stems, seeds, leaves and roots. Belongs to the thiolase-like superfamily. Chalcone/stilbene synthases family.