...also before if we flew home over Christmas we were still considered in the US, with the new ability to access records will we still have to count our time home at Christmas as still being in the states...
...my understanding of this is yes, you will continue to be considered "in the US" even if you leave to return to Canada for Christmas. The concept is thus: if you (as a Canadian) make frequent trips to the US over the/a period considered to be a year, US customs may/will consider you to have closer ties to the US than to Canada, and will fill in the short "gaps" that you have returned during, and rack up the entire period as one long visit.
Remember, the US considers ALL visitors as: "presumed to be intending immigrants", and the onus is on the visitor to PROVE "clear and convincing evidence that they do not intend to abandon their home country". So, US customs can absolutely refuse you (the Canadian) entry if you are "a frequent crosser" even though you have physically only been n the US for say, 100 days in a deemed year.
This is in MHO, after researching this topic vigorously over the past 3 years. I am not an immigration lawyer. See an immigration lawyer to verify this with subtleties, and do your own due diligence.