Yes, as long it is part of your benefits. Still if you say you are getting same # of point with 1 or 2.5 years you already have more than enough time in addition to the 1st year. So even if your vacations wouldn't count you would still have enough additional time to make up for that.So does 1 month vacation will count towards the work experience?
And you just need to provide proof of whatever you want to claim points for, you can just claim one 1 year and provide supporting documentation for that 1 year only. However, being the same position you will probably just get a single letter for your entire experience since you started.
I don't see any challenges with your application.