Yeah it's definitely a big increase in cost; I wonder if this is the new normal for this type of event.
As an aside, I wanna reaffirm that Dendrobium is even more of a monster than before. I'd been having trouble completing the Aqua Shadow EX stage featuring the Acacia Corps up until today when Dendro more or less soloed the bottom path. Both Shadow Acacia and Shadow Dahlia nearly got one-shot by a giant fist and Shadow Cherry Sage got punched out in two rounds before Shadow Lupine could drop off the power up.