Not confusing at all SM,
Look at it this way, 485 is what you apply to change your status to permanant resident! But you still need an AP to travel outside the country. You apply for an EAD to allow you to work inititally, so where in the process do the above facts change.
You still are an adjustee, don't have your permanant residency yet. Ergo, you need a document from INS authorizing you to work which is your EAD. Now if your EAD expires, why would you think that you don't need to renew it to work? There is nothing that has changed in the set up discussed in the above paragraph.
Offcourse the whole scenario changes if you work on your H1. But that means instead of renewing your EAD, you now need to transfer/apply for a H1, which will give you the right to earn money. Like I mentioned in my earlier post, you can always work for free, but for the company to pay you, you need to be authorized.
Regardless of it all, you don't need to worry, go for a renewal, I am sure your company will pay for it since they need you to work and it is definitely cheaper than H1. If it doesn't come in the time your current EAD expires then apply for an iEAD!
Good luck!