Yes, the tub contains a little less powder than 4lb tub of ON casein protein but both have 55 servings because the servings size here is smaller. And this one is a tiny bit cleaner with one less gram of carb and .5 less fat per serving. Both products have 24g of protein per serving so you can straight up price compare this with 4lb ON casein.
This price is really hard to beat for casein protein which is usually more expensive than whey. Also, do NOT use the subscription option because for some reason it is more than the regular Prime price. Could be a mistake in the listing because I don't think I've ever seen that.