The reason it was suggested that you send the 1099B with the return is that it would speed up the processing of your return. Without the 1099B attached it could slow down processing.
My recommendation on the entering of your 1099B transactions is that you consolidate the transactions into one, then add the $5,000 to your basis. If you try to break everything down more or average to spread the cost basis over all 10 transactions I think you are sending a red flag. Whether you attach the 1099B or not, the IRS does have access to the 1099B. When someone at the IRS sits down to review your file, they may not be able to come up with your calculations and when it doesn't match what the 1099B shows, it will cause you all kinds of grief and delay.
Make it simple for the IRS to figure out.
