I'm reading the force move power, though all of them are worded this way.
Under Strength, Magnitude, and Range, it says spend one force point to increase X by the number of upgrades purchased.
The way it is worded makes me think it means one point ever and not one point per upgrade. If that is correct, a person who has purchased the entire tree can, for four force points, pickup a 4 YT-1300s, and throw them Extreme range. It should be noted this would mean he could throw 1 YT-1300 the distance a sniper can shoot and hit someone for 40 damage for 3 force points.
You're correct, in that it's just one Force Point to activate all the Upgrades.
And yes, it can seem powerful... at first. Just remember that buying those Upgrades costs Experience, and you still need to roll enough Force Points to activate both the Basic Power and the desired Upgrades. So for most Exiles, they're going to be limited to a Basic effect and one Upgrade, at least until they manage to increase their Force Rating to 2.
The other thing to remember is that while the F/S Exile is purchasing those Upgrades, other PCs are buying up their skills and purchasing talents. Much like WEG d6, a Force-user runs into the choice of either being a specialist at using the Force and not much good at other things (like using a blaster or flying a starship) or not focusing as much on the Force to buy up skills and talents.
Also, the thing to remember is that just because your Force-user has the ability to lift a Silhouette 4 object, that doesn't mean there's always going to be Silhouette 4 objects just lying around. Unlike Saga Edition, the damage from Move is based upon the size of the object plus any uncancelled successes you have from the Discipline check. So best case scenario, you might be able to wing about 20 damage at a target with a Silhouette 2 object, but most of the time you'll be hurling Silhouette 1 objects for 10 damage instead.
And with Force Points, there's not as many Light Side facings as there are Dark Side facings, and to use those Dark Side facings, you have to spend a Destiny Point and suffer an equivalent amount of Strain. Plus, only one of the Dark Side facings shows multiple dots, the rest are a single dot. When GM Chris was running his "Enemy of My Enemy" module at Reapercon earlier this year, the TK-based F/S Exile had to spend a lot of Destiny Points and suffer Strain in order to use her powers due to the player constantly rolling Dark Side results, and even then had to settle for just the basic effect.