If you add a line into one of the "My Lines" files, WinPicks switches all of the games lines to the new data set. Because of this you have to make sure the My Lines data has enough previous games in it so the "After Playing" trends will produce the same results as when running with the downloaded lines.
You can add lines to the My Lines file for previous dates using the "Copy From" downloaded lines feature in the "Lines and Totals" screen. Once you have enough games in the My Lines files, the results should be the same in Trend Alerts when running with downloaded lines.
The My Lines file starts with an empty database. If you wish to initialize all of the My Lines for the season with the download lines, you can do it, but you need to copy a file in Windows. In the "C:\WinPicks 2007\Stats" folder, the downloaded lines are saved in a file called "cblines.07". The "My Lines" are stored in a file called "cblines1.07". To make them the same, exit WinPicks, and remove the "cblines1.07" file from the folder. Then make a copy of cblines.07, and rename it as cblines1.07. My Lines will look just like the the downloaded lines after that, and you can enter your own lines and keep it up to date.