Hello,
1.
In you case you have set the "Group packages" option to YES and the "Dimensions and weight of grouped packages" option, so your products will be grouped on 40 x 30.5 x 21.6 cm packages which will weight less than 20 KG. Note that these option can make your shipping price vary.
Modifying the handling fee in the Canada Post SellOnline site has no effect on shipping price
You should probably just use the price option of the shipping plugin.
2.
Playing around with the product sizes, shipping 5 products
Anywhere between 1x1x2 and 15x10x2 calculates $8.90
16x10x2 and over makes it back to 5 packages at $38.50, even at as high as 30x17x2.
Changing the weight between 0.490 and 0.010kg has no effect on the price.
You should maybe test it with bigger difference on weights.
Also, note that the when the group packages is ON, the packages dimensions will be set to :
- The 2 bigger dimensions of all products
- The total of the smaller dimension of all products.