at wot, the pcm is not using closed loop to control fuel, rather it is putting more fuel in (richer than stoich) to increase torque because on nearly all spark ignition engines, max torque is around 12.5:1 rather than 14:1 which is stoich. also at wot the spark timing is not as advanced as part throttle.
at part throttle, the pcm is controlling the a/f in closed loop, looking at the oxy sensors to know if its lean or rich and adjusting the fuel. and at part throttle, the spark timing is advanced farther than at wot.
the combination of those is why you can have knock in some situations and not others. the base spark advance number is plucked from a table - think of an excel spreadsheet with engine speed on one axis and engine load on the other axis. there is a different value for base spark advance in each cell on that spreadsheet. so, to help your tuner know how to fix your part throttle knock, you will want to tell him/her at what engine speed and what throttle setting (light, moderate, slight acceleration, moderate acceleration, etc.) you are experiencing the knock. there could be just one or two of those cells where the base spark advance needs to be changed to eliminate the part throttle knock.