If you want to claim that judgements of FMJ's sales can be made from the rankings, then you should present your equation for knowing the relationship between rank and sales volume and also your knowledge of how the sales rankings vary over time.
Saying that being in the top 50 is great is meaningless unless you have some basis on which to judge.
At the moment all that can actually be said about the rankings is that they have improved relative to 6 months ago.
But what that improvement means is outside our knowledge.
It may mean 1000% more sales or 1% more sales.
You may dismiss me as old grumpy whatever, but that doesn't change the facts.
Its just basic science thats all.