Phosphorus calculation help?

I have a 16 year old furbaby and have been supplementing him with Sheba pate turkey & chicken flavors. I contacted the company to ask them the % of phosphorus (also for anyone else who feeds Sheba). Then promptly realized I'm too dumb to know what to do with the info. 

SHEBA[emoji]174[/emoji] Premium Pate Chicken Entrée - 0.31% or 0.31g/100g

SHEBA[emoji]174[/emoji] Premium Pate Turkey Entrée - 0.31% or 0.31g/100g

I know there's such a thing as "as fed" and "dry matter value" etc etc. I feed him one 3oz (85g) can a day to two-or-three times a week and am just trying to figure up what one can breaks down to. Math just isn't my strong point. 

So if he eats a total of 85 g daily, there's 78% moisture in one 3 oz can, can a math whiz tell me the total phosphorus he's getting? Also, if it's an ok amount or too much for a cat his age?

If each 3 oz. can is 85 g, and 0.31% off that weight is phosphorous, then there is 0.0031 × 85 g = 0.2635 g  of phosphorous in each can.

BUT percentage wise, I generally figure if they give me the figure on an "as fed" basis, then I multiply it at least by 4 to get the dry matter percentage, which is what you are looking for for kidney cats.  It's just a rough measurement, but when looking for food for kidney cats, I went thru so many foods it was just easier for me.  So at .31% x 4 would be around 1.25% phos.  For me, this would be just above what I would normally find acceptable, HOWEVER, our Vet always said "feed them whatever they will eat" when talking about our kidney cats.  Truer words were never spoken

Are you familiar with this site:  http://www.felinecrf.org/canned_food_usa.htm#canned_usa  It lists cananed food in order of the amount of phos in it on a dry matter basis, however, I Sheba isn't on it. Many foods ARE, but obviously not all.