Modbus for Kamstrup multical heat flow meter?

Due to a slight mixup I have ended up with a heat flow meter (Kamstrup Multical 403) with a ModBus output module and a mbus to USB adapter to connect to my EmonPi. I had originally intended to get MBus in the flow meter, but messed up. You say potato and all that.

Instructions for connecting up a heat flow meter tend to focus on MBus variants, though for one type it seems to be recommended to use a ModBus variant, so suggestion is that either works at some level (I’ve actually lost the documentation page now, but recollection was there didn’t seem to be anything fundamentally different?)

So I’ve got two options. Either get a ModBus to USB module from OpenEnergy monitor, or change the ModBus comms module in the flow meter for an MBus module. The modbus USB dongle is about 30 pounds, the replacement comms module is about 100 pounds. The modbus dongle is showing as available in the shop, not sure on the availability on the mbus comms module yet.

Is connecting my heat flow meter over modbus going to work? Do I loose anything by doing so? The modbus<->USB module is a lot cheaper than the mbus module for the heat flow meter, but I don’t want to take the path less travelled.