Is it necessary to perform calibration steps for the use of the MAX dye in duplex RT-PCR experiments on different cyclers?

It is not necessary to perform calibration steps with MAX dye.  For instruments from Applied Biosystems, simply use the VIC channel/filter for the detection of MAX. The emission maxima of MAX and VIC are very similar (557nm and 554nm), respectively. On the Rotor-Gene Q, use the yellow channel. On the BioRad CFX, use channel 2 for MAX detection. On the LightCycler 480, use the combination 523 nm (Excitation) / 568 nm (Emission).  MAX was chosen as a second dye label because VIC label is protected by ABI and HEX showed more crosstalk in our experiments.