Why were AlexaFluor700 and AlexaFluor750 used instead of the much brighter tandem dye analogues APC-AF700 and APC-AF750?

Only strongly expressed antigens such as CD8, CD3 and TNFa are conjugated to AlexaFluor700 and -750, delivering sufficient signal strength while markedly reducing compensation requirements as compared to the tandem dye analogues.