Dave...with due respect to your battery knowledge, my 3 stage Balmar charger works just fine with my sealed AGM's. 14.2 Volts Bulk charge then stepped down to 13.1volts float. It also has adjustments for different rates for gels which CAN be damaged by the higher voltage wet & AGM's can take.
Also...around 12.25 V at rest is 50% of capacity...I don't think you meant to imply that 10.5 V (flat) was half capacity. No one should discharge their batteries below a RESTING voltage of 12.25V.
Another link Dave which I think you will find fascinating given your expertise & technical orientation is:
I would be interested in hearing about anything you disagree with him about if you get around to looking at it.