Confused about LSAC GPA

[TruckDrivinMan]

So how exactly do they change your undergrad GPA to fit their table?  I see the chart that has the number grades such as 98-100 is worth 4.33 and 90-92 is only worth 3.67 etc.  However, from what I understand, my transcript (from the University of Arkansas) will none of this information on it.  There are no number grades, nor are there any A+ or A-.  My GPA according to UA is 3.91; I don't remember how many of my A's were in which range of LSAC's system -- hell I'm pretty sure I never knew for most of them. 

So is LSAC going to just assume that some of my A's were A- and revise my GPA?  Do they contact the school for more detailed information?  I know some of my teachers didn't even have a number-based grading system. 
Help I'm confused lol 

[Ninja1]

If I remember right, they make -'s worth X.66 and +'s worth X.33 (or something like that). Other than that, I don't think they change your GPA at all.

Unless you have a ton of +'s or -'s, your GPA probably won't change much. Mine went down like .02 IIRC.

[TruckDrivinMan]

thanks for the info Ninja.  There are no pluses or minuses on my transcript lol, so I guess it won't change.  As far as I know, my ug school doesn't give +-