Hi, I'm sorry if this has been asked before. I skimmed over some recent entries where members have posted informative articles on housetraining but none that addressed my specific concern.
My 6 month old Shih Tzu is doing well with training; he usually lets us know when he has to go (he does a cute, low bark) and even when I leave our home to go shopping for a few hours he doesn't pee in his playpen. I crate trained him and he still uses it to sleep at night but he prefers the space during the day in his playpen.
However, if I leave to shop during a window where he has to poop (I have his poop schedule memorized [

] 

I'll come home to poop, but not pee. I've even left him in his playpen as long as 5 hours and came home to nothing but a little bit of poop and I immediately take him outside to pee and he usually goes for a long time. [

]
My other concern is that if I'm home using my computer while he's in the playpen, and he feels like he has to poop or pee, he'll bark at me to go outside. But, the few times I've let him down on the floor to see if he'll let me know when he's down there - he'll sneak into the other room to poop, but not pee. LOL
I have a good attitude about it and I'm hoping he'll come around soon since he's made good progress since he doesn't pee in our home but just was wondering if anyone has insight as to why he might be doing this and what I could do to help. [

] Do you think that he doesn't know the difference or do puppies maybe have a harder time holding their poop? He'll bark at me urgently when he's in the playpen to go outside... so I'm wondering if he's telling me, "Hurry up, Mommy!!! I can't hold it anymore!!!" LOL
Thanks so much for reading. [

]
Jessica & Cocoa
EDIT: Just wanted to add that these "accidents" are very few and far between. I minimize any time where he can freely wander to a very minimum but every once in a while I do allow him to walk around the house with his Mommy's close eyes on him. I allow him mostly to walk around AFTER he comes in from doing his business as a little reward for being a good boy. Then it's back to his playpen with all his toys and a little bed I bought him. [

]