According to robot gear, the V2 of this driver is more like a 4988 with respect to pins,
“This revised version of the DRV8825 breakout board has been improved to have an interface nearly identical to the A4988 board and pin compatible.”
I can only assume this is why your microstepping pans out differently to ours. According to the Rumba Wiki, having a jumper on the 3rd pin pair should result in 16x microstepping, making the steps per mm value for the Titan extruder 417.5. A4988s don’t have a specification for one jumper on the 3rd pin pair, so it appears the V2 8825 defaults to 32x in this case. If you feel like changing it back (which isn’t really necessary) try using the A4988s definition for jumper placement to result in 16x which is a jumper across all 3 pin pairs.
Will running your extruder at 32x make much difference? well… no. The added resolution will give you no measurable benefit from a print perspective, but you may loose some motor torque and potentially generate a bit more heat in the process.