When to apply dependent Visa for Belgium

I'm from India and I have just started the process of Belgium Visa B by my employer the plan is to get a dependent Visa for my wife and to travel with me when the assignment starts. My company is telling me that once my Visa is arranged then getting a dependent Visa for my wife very fast but my understanding is that if the process is started together then it's easier and quicker.. please let me know which is better?
TIA

already mentioned many a time here that applying together is faster