Not sure but would love to hear others responses.
I'll just say though don't go smaller than 3/16x5/16. I also got the 3/16x5/16 off amazon and it works but prior to that i had some 3/16x1/4 (something the guy i bought the kegging system off craigslist included as an extra) and it was incapable of stretching over 1/4" barbs without tearing. The 5/16 is just enough to handle it.
Though i do have the issue of losing carbonation from within the lines. No leaks anywhere in the system, but who's to say thats actually is the smaller diameter lines fault. At some point i'll get get around to ordering some 7/16 OD tubing and see if there's any difference.