Hello Jandrabek,
First thing first, I am very sorry for such an inordinate delay in responding to your message. The entire team was away for the last week on account of the biggest vacation in our part of country.
Good thing is that we are now back and I should be able to take care of all your queries/ concerns in much shorter span of time. To begin with, let me take care of your first question-
1. Admin fess Vs Vendor commission- The plugin as you see provides 2 methods to share the revenues between admin and vendor: admin fees and vendor commission. These setting options are located at wp-admin>> WooCommerce> WCMp>> Payment
a. Admin fees- When you set the payment mode to admin fees, it means that all commission options provided by the WCMp plugin( product specific, vendor specific and the payment setting specific- these 3 are set with the priority basis of highest to lowest) would be calculated as admin fees. So if you set admin fees as the commission option in percentage basis, followed by setting up 20 as the commission with an individual product then admin would gain 20% of the order value. Rest goes to the vendor.
b. Vendor commissions- When you set the payment mode to be vendor commission and follow the same steps as stated above then vendor gains 20% of order value and rest goes to admin.
Check out the knowledge base article https://wc-marketplace.com/knowledgebase/setting-up-commission-and-other-payments-for-wcmp-v-2-1-1/ to use the option more effectively.
*** Please do note the priority levels of the commission modes, highest one is product. If that is left vacant, the plugin checks the vendor specific commission. If this one is missing it looks at the global setting one and if all are missing then the entire amount is either paid to vendor or admin as per the setting option”Revenue sharing mode.***
2. You have mentioned a test case where you have setup product price as zero. This won’t work out because the basis of commission is going to be the order value which needs the product to have a price.
3. The testing mode option present at wp-admin>> WooCommerce> WCMp>> Payment is to test the PayPal Masspay payment method VIA sandbox mode. Sandbox mode, allows you to receive and distribute payments without paying actual money.
Let me know if the above shared information helps. Awaiting your response.
Best regards,
Sandeep