The Consequence is reduced for purposes of recovery, that does not mean that the consequence slot is free instantly.
The Slot is still occupied, and the consequence is still there until the end of the scene. Unless you use the shrug off option and that only works a limited number of times per scene.
So, since a ritual is one scene, you can't take a mild consequence, have it disappear instantly and then take another.
Taking that into account i would not worry about balance to much. It's not that big a deal.
Rituals are explicitly stated not to be limited to a single scene of prep time. Taking extra scenes is a listed method of reaching the Complexity. And the Declarations made are generally described as separate "mini-scenes" as well. Assuming your GM imposes a maximum of one scene for your ritual every three hours (a steeper restriction than I would impose normally), a character with Inhuman Recovery can pull 18 shifts out of that power alone in an average workday, and still have a couple of hours to relax before getting a solid night's rest.
--First, inflict a minor consequence on yourself. Shrug it off. 2 shifts.
--Inflict a second minor consequence on yourself. It be removed at the end of the scene, by being reduced below mild. 2 shifts
--Inflict a moderate consequence on yourself. It begins recovery immediately, and is treated as if it were Mild, removing itself at the end of the next scene. 4 shifts (End Scene)
--Skip a scene. 1 Shift. All Consequence slots are cleared. (End Scene)
--Repeat above steps. You have now grabbed +18 Complexity in twelve hours. You may add your Lore to this and begin channeling the majority of effects immediately. If you're willing to stay up late, you can go up to 27+Lore shifts without much trouble, which is often enough for an outright Death Spell, Victor Sells style.
Oh, and Inhuman Recovery helps you stay awake longer too. Spend a couple days opening and reopening wounds, and you will be able to level a city block or two, bind (not
contain.
Bind!) lesser heavyweights to your will, or unravel the outer wards of Edinburgh.
And that's just with Inhuman Recovery. Upgrade it to Supernatural recovery, and you throw around nigh-infinite complexity rituals, and do it relatively quickly.
A character with Mythic Recovery, Thaumaturgy, and a week of time off could pull off a Ritual easily exceeding 100 complexity. That's enough to break through a maximized Legendary Discipline roll and Take Out (fully consequences bypassed) a character who has the Mental Equivalent of Mythic Toughness with FIFTY FOUR shifts to spare for things like extended duration. I suspect Mab herself could be enslaved to the with of such a ritual, at least for a while.