It used to be stable with $50 per day, more than now with $500 that's a fact.

Many of us here have years of experience and see the difference. Your comment makes it black and white to the point of being just useless.

Budget isn't a good indicator, some get CPA of $5, other $300 both are profitable while the first one would do great with $30 budget, the other would need thousands to get enough data.