Transfers are based on Use Year. If you have a June Use Year, you are in your 2012 Use Year and may transfer to another member's 2012 Use Year. At this time you may transfer points from your 2012 Use Year and/or your 2013 Use Year (into another member's 2012 or 2013 respective Use Year). Two transfers may be made with one phone call to MS for the current (2012) and next (2013) Use Year. (Those with a February or March Use Year could transfer their 2013 and 2014 points with one phone call.)
The Use Month does not really matter, the only thing that does is the Use Year itself (2012, 2013). The points will retain their original Home Resort status as well as the original Use Month/Year regarding banking deadlines. Transferred points may be banked into the next Use Year but cannot be borrowed into the current Use Year.