Look at the claims. If you are doing anything that the claims cover then it doesn't matter what else you are doing differently ... it is an infringement.
A good patent will issue claims that are both general enough that it covers all possible new and novel iterations of the patented idea, and not be so general that the claim is rendered useless ... it must be truly new and novel and specific enough to point out what makes it new and novel.
You know, you can also always contact the patent owner and work out a licensing deal. 3-6% of profits isn't bad, if you have to spend 3-6% to work around it or if the workaround is inferior. Plus if they get a licensing deal and have some weight they can make a great partner.
OTOH, I find that often the innovation involved in working around a claim can result in something truly better and new and novel, and if it doesn't (or the workaround seems it might still infringe) I'll abandon it. There are a billion fresh ideas just waiting to be seized, don't waste your time on cheating on a used one.