I like calling late season, I don't do a ton of it (will call morning and mid day) what keeps me from calling more is usually by the time calling can be consistent, i'm hunting a couple particular bears, and I try to stay as low impact as possible on those bears..... they will circle your wind if they can (in my experience) and especially in thick country like it is here.
my calling has evolved the past few years on accident. I usually draw a spring tag every other year, and the years I don't, i'm calling for lions. the amount of bear I have accidentally called in with lion vocals is interesting, and that's pretty much how I call when targeting bear now.
bear are proven to steal lion kills often, so it's no surprise it works. my lion setups start with a couple of minutes of distress, then lion vocals.... painting the picture of a lion making a kill, then using communicative calls like they know another lion is in the area.
if specifically calling bears, I will do another little distress period around the 30 minute mark, and make sure you call for at least an hour for bear or lions.... bear seem to like that 40-50 minute mark to come in.
setups are very important, if you give them a path to circle down wind, they'll use it..... lions don't care much about wind, so wind is another factor calling bear.... you can use that to your advantage where you set the call, bringing them into a spot you'll see them.
my biggest hangup is I love sitting behind the glass in the spring, and I spend a lot of time calling on either end of bear season targeting lions, so I don't call bear a lot.... it is pretty exciting when a bear comes into calls, and it varies a lot how they do, some will charge in, some will be very nonchalant about it, almost like they don't here the call and they are just walking over there for an unrelated reason, haha.
I would probably call more in a high bear biomass area, that's not the case here, so I mostly look for big sign and work on patterning that bear..... when I find a big boar, I don't want to chance disrupting his habits by potentially calling him into my wind.... I put a lot of effort keeping my scent out of an area i'm trying to kill a big bear in.