Is it possible to get S+ in the VH stage event dungeon without the score boosts?

-25% PATK and MATK, and -40% MDEF, are both enormous debuffs. Debuffing your attack that much makes clearing the already tedious stae far more tedious thanks to there being no x2 speed, and lowering your defense to such a degree makes the harder sub bosses one/twoshot you.

After several attempts I managed to get to 1.06 million using the 10% score boost (-30% healing) for the last fight, and only the megalixir, and now I just feel deflated after having come so close.