You have given enough information in your original post. You said this is a business. Maybe your area is different, but in my area we have been told you do not dr packages at businesses. We have been told you can not even accept signed dnotes at businesses. Ask your manager for a copy of the companies proper dr methods sheet. Read it carefully and follow all instructions on it. In my facility we are required to sign that document yearly. If it's a business run from thier home thats a dirrerent story. You can dr at those locations as long as the packages follow the out of weather out of sight requirements and are not left where their customers enter the building. The garage door opener should be left in a location at the home where you can find it, use it to open the door, leave the bundles, push the button to close the door and leave the opener inside the door before it closes. You can then leave a dnote for the customer letting them know you were there and left the packages inside the garage. They can then put the opener back where they leave it daily for you. But, again, this would only apply to residential stops, not businesses run from a commercial location. You will be held accountable for any packages left at businesses that come up missing, and that's what your manager is trying to tell you, but hopeing you will leave them anyways to prevent the send agains.
If going this route causes the customer to call in a complaint, so be it. You need to cover your backside, not theirs. No manager can tell you to leave packages at a business location. If one does, ask for it in writing.
Heres a sample of why you allways follow proper dr methods. Had a driver deliver to a third floor of a tripple decker. Allways were high value packages requiring signatures, controlled through the high value procedure. One day he gets a package that the company dropped the ball and it didn't get controlled properly, nor did it have a signature required stamp/sticker on it. He had been asked in the past by the customer to leave his packages at his door on the third floor, since noone but his family goes to the third floor. Driver decided to leave the package. It turned out the package was insured for $40,000. You guessed it, the company goes after the driver for restitution. Went all the way to an arbitrator that told both parties they should try to come up with an agreement, sent them out of the hearing three times to find a resolution. The sides settled on the driver having to pay $11,000 in 30 days or lose his job. I'm glad the driver was a great guy, very well liked by his co-workers. We held a fund raiser for him and raised close to $9,000 to help him out of this jam.
Please follow all proper dr procedures. It could, in the end, save your job, or save you a lot of money, money that you work very hard for.