i checked it out & i wrote a function for my app, but depend on various version of excel or other reasons that i dont know, the xml output is different, & in many cases my function doesnt work correctly, i wonder if a complete function exist that support all cases.
What errors is your function giving you. If you are using XML that conforms to standards (which I would imagine excel should output) then there shouldn't be a problem in using something like domdocument. Which PHP version do you have? I suspect your function doesn't work correctly if anything. On php.net you should find some help in the comments section for people whom have worked on recursive parsing of xml using xml_parse();
It shouldn't matter what is in the XML, if your function works correctly it'll be fine for whatever XML you give it.