I posted a picture of a truck that lost the TC which had frame mounted tie downs..Drove right out from under it with acceleration,I assume..

Any tie down system is subject to failure depending on the nut behind the wheel..
I to have used the now primitive tie down systems of the past which never failed me in any way with tough use in the mountains of Idaho..They just worked but are considered primitive by internet standards today..
The happi jack system works just fine if used correctly as does the frame mounted but as you can see,the frame mounted system can fail...
To the op...Nice job!!!