The trading volume includes all funds in your MultiHODL deal - initial collateral and the borrowed after using the Multiplier feature. For example, the operation with input 1000 USDT and Multiplier x20 means that its volume will be 20 000 USD.
The trading volume counts both open MultiHODL and close MultiHODL events. For example, when MultiHODL is opened with a total volume of 10 000 USD and is closed with a profit of 500 USD - the volume in your Loyalty program will be 10 000 USD (while opening the MultiHODL) + 10 500 USD (while closing the MultiHODL) = 20 500 USD.
In summary - when you use MultiHODL, your trading volume always includes not only your initial collateral, but the whole deal funds depending on your Multiplier level, and the volume increases for both open and closed MultiHODLs.
This model assures your trading activity improves your account's Loyalty level in the most efficient and fast way.
P.S. In the nearest future, besides the MultiHODL products, other Loyalty level increase options will be added.