Finally! The house is finally level and stable.
I thought about it all last night – whether to rent the jack hammer again for $40 and chip out more concrete to put align the bottle jack with the stable part of the sill plate and rim joist. I wracked my brain to find another way.
The way, it turns out, was simple. The house was stable, yes, but it was still holding the add-on down. So, I screwed the new screw jack stands up and pumped the bottle jack until they are both up high enough to add the last course of bricks in between the foundation and sill plate.
The five little red screw jacks at the end in question were easy to screw upward one-at-a-time. Together, they had enormous lifting power.
The gas line, with the hole through the rim joist elongated, sits stably on the rim joist hole.
While down there, I talked with my sister in England via WhatsApp. Between jacking and bricking, I weeded.
Now that the lift is complete, on to the main floor living room drywall and window.