The formatting on Office is partially if not entirely driven by the printer driver. Since an iPad and many pads don't have a printer you can't get the "printer metrics" to keep the formatting from getting off kilter.
The Pages you can get on the iPad is great, allows editing and Numbers works fine but your requirement likely is beyond what most want.
Did you try a Windows 8 RT tablet? It's a tablet and comes with a debonaire Microsoft Office Suite.
What is the best and easiest way to be able to edit Microsoft Office Documents from an iPad including complicated Excel Spreadsheets without messing up the formatting?