Thank You for your respond I think that this meter is not accurate to measure AVG and PEAK power. You have the reason.
Use the tune function on your rig if (you have one) which sends out a steady unmodulated low power carrier to optimize the tuner adjustments.
Alternately, use CW mode in low power to tune. What's good for CW will be fine for SSB as well.
Readings in SSB mode are pretty much useless other to demonstrate that something is going out.