Double maintenance

Yes, can be allowed.  You are already paying.  The point is, she is private.  You cant trace private ppl income, even if they are earning handsomely.  This will continue till the day you die or she dies ie paying maintnence to her.

It depends on the nature of your first order of payment in DV proceedings, which I believe is interim maintenance.

Even though there is another order for maintenance u/s 24 HMA (interim maintenance) made by Family Court while a similar maintenance is being allowed under the DV Act by Magistrate, the amount of maintenance that your wife gets will be one only which ever is higher.

You can benefit from the advice of Mr. Vijay Raj Mahajan.

A private tutor may earn equal to or even more than that of  teacher.

Hope you could prove the earnings.