Samsung Galaxy S4 - Sync times not matching times well mail is being 'fetched'?

[TechAddict]

Trying to fathom out what's happening here and why, and what it's affecting.

I sent myself an email to test notifications etc. As an example it arrived at 18:25. So then accounts are being 'polled' according to my schedule. Yet when I open up Settings / Accounts / Email is shows the accounts were all last synced at 18:11, the last time I hit the 'Sync Now' button at the bottom? Surely at least one of them should read 18:25, the time when it did in fact last 'Sync' and retrieve the sent email??

Any help appreciated.