Kokila according to Nani is supposed to be moulding,training Rashi into being a good bahu ...Kokila is doing that by the way and means she knows.
Kokila is very authoritative in her character so that shouldn't come as a surprise that she acts in this manner.
However money in today's day and age is not relative to anyone .Kokila feels this is a sheer waste of money and shes fully entitled to feel as such.
Once the training is over Rashi can go and make 6000 worth of calls ,which she no doubt will.
The biggest difference between Kokilas behaviour to Gopi from Rashi is that she actually wants Gopi to be the pinaccle of the household.
She wants to be proud of her 'meri Gopi bahu' and she goes out of her way to pronounce that Gopi can cope with household chores.
So what if they have money... its still someone's hard earned money - even the richest people in the world dont throw their money wastefully so that's not an acceptable to anyone.
Anyone who thinks they are entitled to waste money needs to be taught a lesson in being frugal so Kokila did the right thing...
and why should anyone be so concerned for the personal rights of a person like Rashi who is down right malicious,scheming, and heartless ..how many times has she caused Gopi to be in pain?
What goes around comes around ! No tears lost here for Rashi getting a taste of her own medicine.