there is slightly more water of crystallisation in the second product and this will affect a calculation of the weight of product to add to a solution -- I think the x in the first product formulation is just ignorance, throw away the x and reorder the Sulphurs and the Oxygen content. Conventionally the product would be written Na 2 S2 O3 and suitably subscripted...

you make up solutions to add a fixed weight of the thio to a fixed quantity of water
the following solutions are chemically identical
158 g of anhydrous thio sulphate in 1 litre water
248 g of Na2 O3 S2 5H2O
266 g of Na2S2O3 6H2O

having said all that , one of those hydrations is unstable and the product will absorb or lose water to the environment.