Of course. They tell you how to create budgets but not how to import already populated Excel spreadsheet. I also phoned Reckon Technical Help, who told me you cannot import budgets created in Excel into Reckon at all. I was dubious of that answer so thought I'd check with the community.
There is no direct way to import a Budget from Excel to Reckon Accounts. However, you can export a budget template from Reckon Accounts to an IIF file (File > Utilities > Exports > files to IIF > Budgets), open it in Excel, replace the values with your values from Excel, save the file as an IIF file and import it back into Reckon Accounts (File > Utilities > Import > IIF files).
Hope this helps.