I'm confused by the use of the word "successes" a few places in the rules. Is it supposed to mean the same as "degrees of success"? Or is it degrees of success +1?

Example:

Modified Characteristic is 60. Roll is 25. How many successes?

a) 4 (1 success + 3 degrees of success)

or

b) 3 (3 degrees of success)

Stat of 60:

Roll: 55 = Success

Roll: 45 = Success, 1 Degree

Roll: 35 = Success, 2 Degrees

Roll 25 = Success, 3 Degrees

If you counted the other way, the second bullet from an Autofire attack or Macrobattery would automaticaly hit.

I believe I understand "degrees of success", Quicksilver. The question is about the word "successes", as in:

"Crit Rating: This is the number of successes the shot must have to score a critical hit on the target." (page 219)

Oh! sorry, I totaly missunderstood your question.

I think the first success counts in that situation. So yeah, your example would have resulted in 4, not 3. I can't quote a spot where it specifily says that though.

I've come to suspect that there is no universal definition of the word "successes". It's just imprecise rules language.

The rules for a stern chase (page 216) clearly use "successes" to mean "degrees of success".

The "mind scan" power (page 164) talks about "degrees of success", yet if "2 successes" means "2 degrees of success" then merely "succeeding" on the Focus Power Test means ... failure? (With the caveat that I've barely skimmed though the psyker-rules.)

The rules for mass combat (page 292) talk about combining "successes", implying that even a plain ol' regular "success" will be counted.

The "Disengage" action (page 214) says you need more "successes" than the enemy ship to ... succeed. Here, I think succeeding gives you 1 success.

The rule for starship Crit Ratings remain a mystery.

I found an example (page 221). A quote: "The gunner then fires the lance, making a Ballistic Skill test against the total of 58. He rolls an 11. Not only is this a hit, but it also four degrees of success, enough to meet the lance’s Crit Rating."

To me, this implies that the Crit Rating rule is supposed to refer to "degrees of success". (Option in the OP.)

Bonus question: Am I right that void shields do not make a difference when it comes to getting a critical hit based on a battery's Crit Rating? They only subtract "hits", not "degrees of success"?

They only subtract hits, if one or more hits still hits the ship the crit will take effect.

This threat is kind of funny because we have experienced the same problem around our table. Counting degrees of success to land a critical and therefore, in some situations, counting degrees of successes for total hits landed with a battery. It becomes a bit confusing to have to only count degrees, in some situation, and also the first success in other situation. I think we are going to change it, so the first success always take effect. And I think this is what is intended in most cases.

It would be strange to have a skill test fail, with a mere success.