They don't care how many times you come and go. If the border guys, who have all your dates let you in your in. IRS is only concerned that you spend less than 182 days in the US to meet the Substantial Presence Test or they want some of your money. Taxes etc.
We have filed the 8840 for 10 years. I use the year (2014) as the last year. When I do 2015 it will be done and mailed from the US (in 2016 Feb.) so I will count 2015, 2014 and 2013 as the portions.
I also carry a spare copy (last year) with our passports as I was once asked by the border guard if I was aware of it.
I mail it in the US as it runs Jan 01/2013 to Dec 31/13 etc. Postage is 47c in the US vs international rates from Canada. I have never entered anything in the Visa section as I am a tourist. Visa types are for workers or those staying longer than 182 days. I also have never heard boo from them in 10 years.
Canada and US now have an agreement to track your time so do not over stay your time, as of July this year both sides will show your entry and exit date.
If you go over for even a day or an hour to pick up a parcel you have to count that as a day in the US.