Value of PSA/DNA LOA for Auto if Already Have JSA LOA?

CollectorAtWork

I recently purchased a couple low grade Babe Ruth autographed baseballs for resale with a cost of around $3K each plus or minus a couple hundred. They already have full JSA LOA. The question is whether I should also get a PSA/DNA LOA for these balls, and whether it would add more value to the balls to more than cover the cost of the LOA's. The authentication fee is $300 and then there's the shipping and insurance both ways, which would probably amount to at least $50 on average per ball, so the additional cost would be around $350 per ball. These are low grade balls and signatures, so it's not like one of these might grade an 8 and go for tens of thousands of dollars. I wouldn't even be asking for a number grade, but just an LOA to cert that the auto's are authentic. If I didn't have the JSA LOA, I would definitely send them to PSA. However, since I already have the full JSA letter, so I need the PSA one? These are for resale, so the LOA's aren't for my peace of mind, but for potential buyers. Any opinions are welcome. Thanks.