As the fellows have already indicated your existing fuel is perfectly fine. In years past especially when the four strokes engines became more commonly used the so called four stroke fuels became popular. There really was very little difference other than the total oil content was less, considerably less. Not all but many of the four stroke fuels had a total oil content as little as 14%. This at a time when most fuel blenders considered oil content and sometimes nitro content proprietary information and would not divulge this information to the customers.

Now it seems the first generation of widely marketed four strokes which were quite frankly not very powerful, These early engines did OK with the low oil content but that left a rather narrow margin for tuning error, plus the fact that needling a four stroke is not so obvious as it is with a two stroke, made these fuels not a very happy situation.

Later on when folks started pushing for disclosure of there fuels nitro and oil blends major industry wide wars started in the modeling press that lasted for some years but finally the consumer (that's us) won out and today most blenders do disclose nitro content, total oil content, oil type and sometime even the ratio of oil types if a blend.

One last thought on the newer generation of four strokes most do tolerate a much higher nitro content and some even recommend higher nitro as well as a higher oil content as high as 20% total oil and nitro. Hence the expression you will here 20/20 fuel for four stokes.

So yup your existing fuel is just fine in you little Saito

John