According to EntertainmentEarth, the case assortment for Deluxe Thunderhowl has 3 in the box of 8... and with one Arcee, it is a good ratio for those wanting to complete Maccadam, as less stores will get in the final wave, so the ones that do will have more of the final figures available.

1x Optimus Prime
1x Arcee
1x Megatron
1x Hot Rod
1x Bumblebee
3x Thunderhowl