No, but thinking this through logically.

On 5 x 60mg, you were probably taking your last dose late at night. Since the average effective time period for Mestinon is 4 hours, by the morning you were "empty". Taking 60mg when you wake up, was not quite sufficient, and so you were always a little behind throughout the day.

By taking 120mg first thing in the morning, you get enough for your eye to be ok. Throughout the day your level would be dropping, but it seems enough.

The 4 hour working period for Mestinon is an estimate. A more accurate estimate is 1.75 hours halflife, so that if you start with 60mg after 3.5 hours you are down to an equivalent of 15mg. So starting with that higher dose, keeps you that little bit higher through the day.