Your lawyer advise is sound. Although there is no particular order that discharge or quash should happen.
In fact, you can file for quash in HC and discharge in trial court, as long as there in no stay on the case from from HC. Having said that, if you are A1, until and unless there are absolutely no allegations against you in the 498a, quash is near impossible. I have seen plenty of SIF members (A1's) who failed to get their 498a quashed. After spending money and time, they did not get the relief.
What grounds are you filing the discharge?