Depends on what you’re looking to get out of the exercise and how challenging it currently is.
Generally speaking, increasing the weight of any tool by 50% is a huge jump and will drastically change your performance. It’s an option, but it’s probably not the best one.
I’d consider changing some of the other variables:
You could decrease between round rest and/or increase round length.
You could increase the distance and/or run faster and/or change the way you move (like do walking lunges instead of a run, bear hug it or zercher carry it instead of having it over a shoulder).
You could train different individual strikes in each round, like right arm-only or knees only, instead of mixing everything together.
You could play around with the ground-pound vs slam ratio. Instead of 90 seconds striking and 30 seconds flipping, or whatever it is, increase/decrease them inversely but monitor them and progress accordingly.
You could increase the “slams per round” and/or increase the total number of rounds done.
Basically, there are a lot more options than you think for making the workout more difficult. They’d all work on improving conditioning, whereas going up to a much-heavier bag will, at least in the short term, reduce the conditioning effect because the strength element of the drill has increase.