Post patrol rating

It's something that I have noticed lately and I wonder if someone could help explain to me about the post patrol rating for the USN campaign.

The game mentions (and I cannot remember where) that after each patrol you must obtain a "Good" rating for the completed patrol to help you gain promotion later on, yet there is zero feedback about your patrol rating, you just get confirmation of your tonnage and a medal. I have completed my fourth patrol and I have been promoted to Commander, yet there is very little more than that. I have tried checking in the patrol report too and all that is listed is your sinkings by date.

I was looking into the config files and I noticed a line in the career track.cfg file and I noticed a rating gained line which has given me a score of 3. Anyone know what the high and lows are?

Here is the section I am referring to (highlighted in bold), it's pretty much the last entry in the file;

[CareerTrack 1.CareerStatusSave 73]
ID=ID
Reason=CSS_PatrolEnd
NameDisplayable=USS Halibut (SS-232)
CurrentDate=1943-07-29 11:18:48
RenownGained=4680.000000
RatingGained=3.000000
TotalTonnageSunk=72746.000000
MaximumTonnageOnUnitSunk=10036.000000
EndBaseIDLink=PearlHarbor
EndFlotillaIDLink=PearlHarborCommand