[wingnut60]

Clev,
Using the same Andersens----ALWAYS place a flat surface (I use AlturnaMats) under the blocks on any surface. Mine are holding up well to the 4600lb pin wt on my Suites. If you place them on gravel, the circular edge is going to sink at different rates, thus placing load on them other than vertical.
I think they are somewhat misleading in their marketing as, in my mind, no thin-edged block is going to NOT sink in an unconsolidated soil/gravel bed. Rightfully, they are replacing them, but it will happen again if you place them directly on gravel.
Or, go to Cummins-type monster wood blocks...