From the web-page quoted above:

One Portable Aqua tablet per quart of water gives you a concentration of 5.3mg/liter.

Using that concentration:

5.3 mg/liter = 5.3 mg/1000 ml = 0.0053 mg/ml

Considering that 10 mg/ml = 1%,

0.0053 mg/ml divided by 10mg/ml gives you 0.00053 %

That last percentage is great for drinking but not for disinfection.

For the response to the original question, as long as the quoted amount of iodine per tablet was correct, the concentrations should be right too...

I still like carrying a vial of free iodine better. Just look for 1 or 2% iodine tincture that uses ethanol, not isopropryl alcohol as the diluent.

Eric