I am not really into the Miles game or the Axis ecosystem, so forgive me if I am not getting it. But based on what you have written, it seems that you are rotating money from Atlas CC to Atlas CC using Snapay, generating Intermiles + some rewards during this process but for a convenience fee levied in Snapay. So far, these are manufactured spends.
Now you are using the Intermiles to get APay Vouchers + some additional rewards, and then using the voucher value as the principal spend, calculating your net rewards.
I have a question, why go through the second part at all. Why not just run the perpetual machine of Atlas to Atlas till it breaks down? What are the limitations imposed by Atlas and why are you unnecessarily constricting yourself to 13K something to generate enough Intermiles? If you do that, how would you determine % returns? Will it be infinite, since there was no principal spend?
Good observations here. The expense increases (1.18% lowest fee option) and no of miles you earn per 15L decreases (all miles at 4%) but that is certainly least hassle way and fastest way to collect miles
In this case I would use Principal spends = card fees + payment gateway fees. Returns % is far higher but not infinite. 487.29% on 15L spends. (115000 miles/ 23600 expense).