As Unitrade catalog denotes you should get a 4 sided perforated booklet stamp - as. The 925a is a booklet of 25. The asi is a booklet single like the as, but because it has the additional i, it has the straight edge, either left or right side.
The normal booklet contains a pane of 5 down x 5 across. Left side has 5 straight edges as well as 5 straight edges on the right. The middle 15 are fully perforated on all four sides.
I may be too late in providing any meaningful information, but for someone searching Canada 925as or 925asi, I thought that it best to clarify the earlier replies to your email.
1. The Scott 925a 5x5 booklet pane only has straight edges on the left and right sides. The top and bottom of the booklet pane has selvedge and hence a perforation of 13.3. Therefore there are only 10x Scott 925asi stamps in a pane (5x left and 5x right), and 15x Scott 925as stamps that have perforations of 4x sides.
2. The Scott 925a pane has a perforation of 13.3 x 13.3, which is the same perforation as the standard sheet pane of 100 stamps(Scott 925). Therefore the only difference between a Scott 925 sheet single and a 925as is the printing company (CBN versus BABN). Which is difficult to detect that requires a statement in the Unitrade that the color of the sky is slightly different. If you collect used stamps then this color variation can be harder to see after a stamp has been soaked.
Therefore, if you want to have in your collection a 100% certainty of having a stamp from the Scott 925a booklet pane then select a 13.3 x 13.3 perforated stamps with a straight edge on the left or right.