@Jodie *********
There is no limit of two visa-exemptions within a calendar year, and not within a one-year period as well.
Nothing “resets”.
What has changed, mandated from above, is the strict scrutinizing of your number of visa-exempt entries and the thorough check on "visa runners" (actually they meant to say "back-to-back border runners").The new approach taken by border officials is intended to ensure that the option to do a "visa run" is not abused.
Now as far as regarding extensions on visa-exempt entries, it does appear that the Immigration offices are indeed only issuing 7-day extensions if you already got one previous 30-day extension on any visa exempt entry
It is totally up to the discretion of the immigration officer you are in front of when you apply for the extension and they will tell you if you can get the 30-days extension, or if you only get the 7-days extension.
The thing is right now it's totally subjective and up to the officer you are standing in front of when you go to stamp into the country for them to decide if you're a "real tourist" or if they think you're milking the visa exempt entry program.
There's just no real concrete clear directive as far as what's what.
Some people with a 30-days extension already on a previous visa exempt entry reported getting another 30-days extension without any issue, however some have reported they only got a 7-days extension issued. So your experience might vary.
60 + 30 + 60 + 7 = a maximum of 157 days per year... and it seems this is regardless of whether you arrived by air or across a land border (some say that for a land border visa-exempt entry, you cannot get any extension at all)
Visa-exempt entries themselves are not limited, even though some believe that unlimited visa-free entries are possible by air. This is simply not true.
Visa-exempt entries are not limited to two entries per calendar year.