I went from ICDD to ICDA, on all of my phones, using global update in OTM. I only have about 150 phones and our call volume is really not that high, even including extension to extension calls. It all worked like a charm. I use a third party call accounting software which has the capability to purge and or archive the processed CDR data so space is not really a big issue for me. Every month I generate a PDF file, with full extension detail, so that any manager can view it and extract what they want. This saves me from having to deal with requests for extension detail information, which I used to get all of the time.