A note on Points Values in Space Combat Games/Insight to Games Design:
Something I learned while working on Battlefleet Gothic way back when. There is no fixed points value for any ship in a typical space combat game. I'll give you an example;
The Federation Heavy Cruiser is listed in the book at 180 points. However, that is
not its true points cost. Its true points cost floats between (if I recall correctly) 165-190 points. It will vary depending on what else is in your fleet, what you are facing and what scenario you are playing. We give it a listed value of 180 because we know that is well within the ballpark and players don't want to make points costs calculations for every battle they fight, especially if they have to take into account what their opponent is taking (you can see the nightmare that awaits there).
Now, this is true of most miniatures games, but the effects of this points spread is exagerrated in space combat games because a) there tend to be fewer units on the table, b) because each unit is just one model rather than several and c) because there are defined classes of unit in the game that cause ships to 'clump' together on a points spread anyway - all destroyers are similar, all heavy cruisers are similar, etc. Not to mention the big gap - some of you players out there are just better than others...
This, incidentally, is
exactly why A Call to Arms: Babylon 5 used Priority Levels. Each PL represented that points spread (you can argue whether the spreads were too wide, and so forth, but that was the reasoning behind it).
This is also why a straight points build/construction system would have enough holes to fly a battle group through, and why we haven't done one. The playtesting to settle on points values is
essential and cannot be replaced by mechanics.
So, you can make a convincing argument as to why the Heavy Cruiser should, in fact, be 175 points, and you would likely not be wrong. So, why did we pick 180 points? Well, there has to be a fixed standard (of course) and there will have been comparisons made to other ships in the fleet and those in other fleets that caused us to settle on 180 points.
This means that, for example, a difference of 5 points between ships is, nine times out of ten, pointless and irrelevant. However, another factor springs up here, the psychology of the gamer - and this is where we try to mess with your heads

Two (or more) ships may be extremely similar in fighting potential in a game but playtesters, for whatever reason, start leaning towards one or the other. To counter this, we might increase the more used ship to five points (or whatever) more than the lesser. It doesn't actually
mean much (if anything) in terms of the game itself (because of the aforementioned points spread on what a ship is really worth), but it is a little dose of psychology to make the lesser used ship a little more attractive.
And that is why you Klingon players now pay more for a D5 and D5W

We just moved them a little further up on the points spread to encourage you to take more D6 and D7 ships in your fleets. But they are still effectively the same points cost...
Now, to come back to the original point, what happens to a ship when it has a weapons, Damage or Shields change (or whatever). The first thing we look at is its points spread, and whether we have artificially made it higher or lower than the average. Most ships are not in that position, and so can stand a change without a corresponding points tweak, because you have an effective 10, 20 or even more points as a 'buffer' on either side. What we have to watch, of course, is how that affects the other ships in the fleet and whether it makes certain vessels an automatic choice (if they are not truly iconic ships, we don't really like automatic choices in fleet lists). If nothing looks like it will be affected, we may well let things pass without further change.
I was going to save all that for a Planet Mongoose article, but now seems like as good a time as any!