Six months is the holding period on "Chevra" & "Kehal".
There is no specific holding period on the escrow shares. The 8k makes that perfectly clear.
upon satisfaction of the account payable
I think they are conducting an internal accounts receivables financing. As money comes in from completed projects, they will pay back the vendor, and then cancel the shares.
They could probably have gone the traditional route, and pay interest and fees on the A/R financing, but this allows them to keep more cash on their books, and looks better when trying to get financing for future projects. It's a smart idea... as long as you have an equal or greater amount of accounts receivables to back up the deal.