I've never used the Adam's soft stop additive. Maxton makes Maxglide, especially for stickslip and hard take off conditions. The few cars I've used it on its done its job. I agree with Dirt and elmcannic, if it's an old car the best bet may be replacing the oil. I should've asked, I assumed from how you described the original problem this is a new car so the oil should be new also?
https://maxtonvalve.com/products/index.php?route=product/product&product_id=108
