IMO that is way too frequent unless she puts on 7500 miles in 3 months. I would (and do) use regular old mineral oil and change at the frequency called for in the owner’s manual. Remember to factor in whether her use of the car is severe or not. Her frequent oil changes fave to cost at least $200 per year. If she drives 15,000 miles per year, she could pay less than $80 per year changing oil at 7500 miles.