I updated all the tokens with a cycle_day of 13 and only used once (3,902).
I ran individual charges on the first 10 and they all worked.
The rest should start running within 10 minutes.

promising news!

For last night's charge job the failure rate was 3.59% across the 3,092 migrated and 3.08% for the 10,384 that were started as Adyen tokens. Seems like a reasonable amount, considering that the migrated tokens are generally older recurring donations.

@Ejegg Looks like a reasonable result. Will we proceed with billing each day from here?

I've just migrated the cycle_day 14 (4,257 more recurring subscriptions). I'll migrate and monitor daily for the next couple days, then if it looks good I'll do all the remaining ones.

Overnight failure rates:
4.09% failure for migrated tokens
3.17% failure for non-migrated always-Adyen tokens.

Again, not exactly comparable because the Ingenico ones are older on average, but seems reasonable. I've migrated 4,074 more tokens with cycle_day 15 to charge tonight.

Overnight failure rates:
3.98% for migrated tokens
3.22% for non-migrated

I've just migrated 4,243 with cycle_day 16, 3,316 with cycle_day 17, 3,002 with cycle_day 18, and 1,892 with cycle_day 19. I'll review again on the 19th and if the numbers still look good I can migrate the rest of them all at once.

Great, Ingenico is preparing to migrate us off of Wells Fargo and to Chase this week. This timing will help us avoid that migration and whatever confusion that may bring. Thank you @Ejegg.