No, on these pumps the timing is a real PITA to set, or change. It is adjusted by the shims under the injection pump. About the only way it can be off, is if the pump has been removed, or it has excessive wear internally, such as the rollers or the cam in the pump. It may need rebuilt.
There are two other things that can make it have the exact same symptoms. One is a plugged or restricted air filter/ducting. But he said he already replaced the air filter, so I crossed it off my list. The other is weak charge pressure to the injection pump. That pump cannot suck at all, so it is dependent upon the charge pump.
I agree with you about the blower vid. Too much smoke, drags down easy and doesn't recover quickly when the load is reduced.
Under edit: I thought of something else that will cause those symptoms: If the fuel shut-off arm on the pump that is either on a cable, or an electric solenoid isn't adjusted properly. It is connected directly to the rack, and if it isn't opening all the way, it limits rack travel, thus causing the same symptom.