From what I understand the VI is different on the two, but the operating viscosity is the same.
Shell ATF | A-Java LLC | Shell in Armenia, the import of machine spares, construction

134/ 236.14
40C/104F viscosity = 29
100C = 6.2

3403/236.10
40C/104F viscosity = 34.5
100C = 7.4

There is no practical difference between a viscosity of 6 and 7. So you may see a little difference with a cold transmission, but not under normal operation.

MB continued to make the 722.6 transmission, install and warranty it, for many years after the factory switched over to 236.14