Engines that have been run on conventional oils most all their life and then switched to SNY will definetly start leaking somewhere.
The SNY oil is so slick and fine it will find any place to leak ( usually seals in older engines) and leak it will, big time.
Now that being said if the motor was ran with SNY all of it life( minus the break in period) then this would not have been a problem cause the seals would still be as soft as a babies butt.
Glad it only took a $1.50 to fix. You got lucky.
Charles