Will some one clarify the distinction between the PI Expert9.0 and the associated PIxls. Which is best used for a new design? We find the PI exper library has some cores like PQ2620,PQ2020 which are not available on the PIxls. When we use the spreadsheet it Auto selects a different core and even if you use the customise option the transformer construct ion details show only the Auto selected core? How do we deal with this?