changing wall mounts, possible problems?

I currently have my Pioneer PRO910HD mounted above my fireplace using an Omnimount U3 Tilt Mount. When i first purchased the mount I didn't know much about it and got sold on something I really didn't need. I wish I had purchased a slimmer profile mount, but I didn't. The omnimount works great and I have another one for a 61". But above my fireplace I'd like to see my plasma closer to the wall. I also don't use the tilt mount.

I was thinking about switching to an Omnimount WM1-L. I am a little concerned about switching mounts because I'd have to create new holes for lag screws as the mounting locations are not the same height. I'd fill the old holes with putty or caulking to reinforce that area, but I'm still concerned. Should I be? Are there any other concerns I should consider? Is there a better idea? I could go with a U3 Fixed...that would save about 1/2" but use essentially the same frame.

http://www.omnimount.com/consumer/pr...f-328aab22a448

http://www.omnimount.com/consumer/pr...1-dee5005db1a2

The thought of leaving it has crossed my mind. It just sticks out so far over my mantle. Going with a non-tilt mount means I wouldn't have to remove the plate from the wall. I'd only change the bars on back of the set. That would save me 1/2", which isn't much, but it might look a little better...

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