Masonry Anchorage - Design Issues

I have a stair condition where the beam pockets in the masonry stairwell walls were not included during construction. The CM wants to face mount a plate to support the stringers, however I cannot get any hilti anchorage to work for the condition, using a 2 bolt condition (8" bolt spacing), I can get a maximum factored load of 3400lbs to be supported, but I need to be able to support 8200lbs. I thought if I went to a 6-bolt condition, this would work, however using 6-bolts I can only get it to support a maximum factored load of 5100lbs.

However, if I go to simpsons anchor design software, I can use a 2 bolt anchor condition with 8" spacing on their Titen HD screw anchors to support 8200lbs. What's the deal? Is there a bug with the profis software? Can Hilti offer any solution here?

I have provided a screenshot from simpson for comparison. If you do the exact same layout in profis you cannot get it to work for more than the 3400Lb load indicated above, while simpson provides a solution to support 8200Lb.

Thanks,
Michael