Yes that i know, at least nakaba should have gave a range of values... for u maybe its pointless but i am keen to get his range of power level. Yes nakaba did made escanor strong but escanor reaches his limit at peak. Nakaba cant manipulate escanor beyond his peak unless he gives him a power up like mel.... real power level is power level doesnt matter weither rhitta siphon it or not... by the way rhitta only stores the excess heat energy, not the power level and that shouldnt be an excuse to hide his true power level. Definitely merlin had read his peak since she have kept in touch with him all this while... to tell u honestly, escanor is being strong is the only guy that convince me why they are called the deadly sins...
If merlin had read his peak then his power level wouldn't be immeasurable though. Odds are that escanor's PL can keep increasing provided he so wills it and the time of the day is right.
As far as I can tell escanor's PL at any point depends on a number of things:
1.- The time of the day. Provided its daytime this is probably not the most significant factor.
2.- Rhitta. We know it absorbs and has a suppressing function when it comes to escanor's power.
3.- How much escanor holds back his power.
The last one is the single most important one when it comes to daytime.
Lets look at the few references we have regarding his power:
The first would be when he fought the vampire king, the next would be when he fought galan, then dolor and gloxinia and then estarosa. He started off the day being immensely stronger than galan considering how easily he could move rhita. We know from merlin's explanation that escanor's power increases as the day advances. However we did see a big boom when escanor's mood was fouled and he melted the castle.
Then we have his fight with galan. We saw his power increasing steadily over time.
Then the fight against gloxinia and dolor. Thinking about it it is weird that escanor was able to swing rhitta so easily considering his power level was barely above gallan. Then again perhaps holding rhitta made him stronger since he meant to release the power it had absorbed.
Then finally the fight with estarosa. The crucial part of the fight was the end when estarosa was overwhelmed. Escanor's power increased dramatically in a very short period, much faster than what we saw when he was fighting galan. What changed? Escanor later made the point that he had to exert himself. So basically escanor willed himself to increase his power at a much faster rate than before. So what does this tell us? It is extremely likely that escanor under normal circumstances holds his power back as much as he conceivably can. But even then we see his power increase at the rate we saw against galan. And when he stops holding back his power skyrockets as much as he can plausibly need. This is why escanor's power is immeasurable. Because he can at will increase it to unfathomable levels. Of course, the time of the day plays a factor as well. His power at noon without holding back is likely to vastly exceed the power we saw him use against estarosa.
Now, that is not to say escanor is invincible. Sure, his max theoretical power likely far exceeds any other being in the manga that we have seen and have yet to see. But escanor's power is highly circumstantial. It is a detriment to his own allies at large, had he fought at the capital any longer odds are that the holy knights would have burned like izraf did. If it is not an option to walk away from people then he can't use his true power either, he could conceivably be forced into a situation where he needs more power but would incinerate people if he did call it forth. And ultimately the time of the day... God knows how rapidly his power decreases after noon. Escanor at almost sunset is not necessarily completely comparable to sunrise escanor.....