Our company is about to start installing Mitel 5000s (we currently install Mitel 3300s, 200s and Toshibas). Most of our sites are less that 75 phones. Our normal numbering scheme is to start extensions at 200, voice mail pilots 400 and phantom DNs in the 500s. To keep things similar company wide I was thinking of keeping a similar numbering plan. (Service technicians know that at most locations they can access voicemail by dialling 400). I would keep all the default 300s feature codes the same, but change 4, 5, 6 and 7 to 334, 337, 338 and 339.
For all the seasoned 5000 techs, are there any drawbacks to making the above changes?