That's actually not correct. Trader Python is 70 million credits. Trader Anaconda is 170 million. Buying a Python sets you back 5.5 million credits
So the question is, does the Python earn 105.5 million credits faster than the Clipper earns 100 million? Nice even number, so the question is: Does one trip in a Python pay more than 105.5% of a Clipper trip?
Clipper carries 240 tons, Python 284 tons. In other words, the Python carries 118% of the cargo of the Clipper. That means the Python makes 18% more profit per trip than the Clipper.
So how much faster is the Python?
Assuming a 2500cr/t round trip, the Python earns 710k, the Clipper 600k. The Python will therefore make the 105.5m credits required to upgrade to the Anaconda in 149 round trips. The Clipper however needs 167 round trips to make the 100 million for the Anaconda.
BTW; the Jumprange on the Python is almost as good as the Clipper with equal fittings. And if you fly on half a tank of fuel, you have the same range as the clipper, and an even better jump range. This is because the frame mass of the Clipper is 400t, and the Python is only 350t, this completely offsets the extra cargo weight of 44t.
I forgot to add 1 fact. I don't sell the old ships (because they still have their uses), so I have to recoup the whole price of a Python.