Yes Mathpac, my corporation told me that they are roling out HAP, all tenants on social welfare rent will move onto it. No idea if this is every county etc. (I think they did a trial in three counties)
I get an email every month with an invoice showing the amount I'm to be paid, directly into the bank account.
You evidently have rental properties in a number of LA areas and seem to have a variety of payment schemes in operation, which must be confusing. There will probably be some short-term pain when HAP eventually replaces the other schemes.
HAP is paid to landlords monthly in arrears on the last Wednesday of the calendar month.