Wanted to add, I tried the OG's site recipe of no garlic and an egg and it was awful, lol. Randomly was at a bar and spoke to someone who claimed to be a cook at the OG. He told me how they make Alfredo sauce. Says it starts in a double boiler, butter goes in and once melted the garlic is added and not allowed to brown. Next comes the whipping cream and a package of powder, which is mostly corn starch with white pepper and salt. They then wait for it to reach 185f, then they vigorously whisk a package of pregrated cheese, he said he assumed it was 100% parm but didn't know for sure. Then it's done. He said everything except the cream and garlic is already segmented for he didn't know the exact measurements. For that reason, I have not yet tried it, but it does sound promising. Just need to find some correct measurements for two servings.
I mentioned in your other thread about "consistency". What you have described here is how a large multi-outlet restaurant chain maintains "consistency" between their individual outlets and even between individual cooks withing the same restaurant. This is to ensure that OG's alfredo tastes the same there in GA, as well as here in OK, and every other state they operate in.
I agree that there is probably more in that packet of "powder" than cornstarch, salt and pepper. Probably other powdered food stabilizers, like carageenan, xantham gum, etc., that help an unstable sauce like alfredo hold together when it's held hot in on a steam table (get it to hot, and it will break).
If you liked the asiago cheese, I say, go for it and use that instead! Asiago tastes a little stronger, and it melts easier, as Asiago is a softer cheese than PR. Where I work, we use Asiago with heavy cream for out Au Gratin potatoes. Yummy!
I would recommend looking at the cartons of cream. Get the one with the highest fat content. This will help emulsify the sauce and melt the cheese. I've made cheese sauces with half-and-half, as well as milk, where I had to use lots of roux in each one, and the cheese didn't melt smooth, but came out grainy. If I use heavy cream, I have to use very little, if any, roux to tighten/stabilize the sauce, and the cheese ALWAYS melts smooth.