The person who wrote this opinion chose to use the common scale of one to ten. This is what Wikipedia says about such ratings:
"The scale has 10 as a maximum score, as a denotation of exceptionally high quality or of another attribute, usually accompanying 1 as its minimum, although some common variants have a minimum of 0."
The score for the samples was 7.75/10. The score for value for money is not transparent. Despite saying that the price of US$1000 is an "incredible value", at least for beginners, let's put that at 5/10. Let's also ignore that fact that he started his thread the day before the library will go on sale for $600.
This implies a score, also not transparent, for the Spitfire App of -6/10. Give value for money 8/10, and the score for the App goes to -9/10.
There are two problems. The first is that scoring on a scale of one to ten does not normally include negative values. Wikipedia calls it hyperbole. Personally, I have never seen anyone do it.
Secondly, as you suggest, the only way to make any sense of this "review" is to say that the evaluation of the criteria was weighted, and that the unstated, non-transparent score for the Spitfire App swamped everything else.
@bfreepro does not say that in his "review".
This explanation does not address the basic problem, which is that his claims about problems with the App are such that many of the users of BBC Pro on this forum should be making the same claims. As a simple matter of fact, they are not.