I might have missed it, but I think the instructions are missing the part where you should multiply py actual * 1.05 to get current year budget with 5% increase.
In Level 200 207
shouldn't this have Set Expression to a*1.05?
In the "MAIN" group, create a "Data flow" step, in "CONFIGURE LAYOUT" use "ACT - DF - Sales LC" as data "a" and select "Previous Year", and use "BUD - DF - Sales LC" as data "b". Set the "target" as "b:BUD - DF - Sales LC" and set "Expression" to "a". Select "CALCULATION DOMAIN" and in the Extend calculation on new tuple for all members of section, select: "Version".