Playtex Drop Ins

Has anyone ever used these specifically with them attached to your breast pump? I read that they can connect directly to your pump and then you can use them later for feeding. Any experienced mamas out there who has used it with the Medela pump in Style?? Say if you pump 2oz each side, can you pump into them again to make a 4oz bottle? Or do you just combine the two into one bag and discard the other? Thank you in advance!!