I don't know where you got that information - maybe modiano made different versions of texas poker? But they are different stocks.
Where did I get that?.... umm.... from Jason himself. He stated as much right here on PCF sometime ago.
Also, any difference in feel could come from a difference in the finish coating & not necessarily the base stock.
Any premium deck of cards are not simply printed on a base stock, cut & shipped out (like it shows in an old "How It's Made" TV show episode available on YouTube) . If they did, that ink wouldn't last very long. So there has to be a finish coat applied. It's a multiple step process. There may even be an intermediate coating applied to the base stock before printing to help with ink adhesion. How thick you lay on the coating, & number of them, will effect the thickness & may or may not effect the stiffness to a certain degree. Depending on the composition of that coating(s).
This image comes courtesy of Fournier....
Also when it comes to Acetate cards in particular, the age & amount of use the deck has will play a larger role in how that deck feels over time. Acetate tends to change in feel over time more than PVC.
I know for sure that Modiano used at least 3 different stocks of cellulose acetate, one for Platinium line, one for Texas, one for Cristallos
Desjgn made of Modiano remind me of Cristallos
More than that, I have 4 listed in the database. TxPoker, Platinum, DaVinci, & the stock they used for Guild, which is the thickest & stiffest Acetate deck known to exist at this point.
Oh shit. Those cards of mine are cristallos
LOL..... oops..... Hey, don't feel bad.... been there.... done that.... got the t-shirt.
I don't have Cristallos (not a fan of 4-pip) but they could be on the DaVinci stock, if not the same as Platinum. They may only use 2 (or 3) for their own branded decks, but for custom orders they obviously have other options.
& finally, when it comes to Modiano specifically. In my testing I've noticed that they seem to have somewhat "looser" tolerances than other manufacturers. The thickness & flex from deck to deck, even within the same line, varies a few ten-thousandths more than most other brands. This isn't a knock on 'em really, as you'd never know that unless you started measuring to the degree that I use in my measurements & testing. You can't feel it. But, it is a measurable variance.
But yea, anyway, the old stock Desjgn & Modiano's Texas Poker line are the same stuff. Even though the database shows Desjgns being slightly thicker & stiffer, the difference isn't something I could pick out blindfolded. Probably just Modiano's normal manufacturing tolerances.