Yes, the posted execution plan just shows the plan for:

DECLARE @ISLEAF BIT

SELECT @IsLeaf = IsLeafAccount FROM Account WHERE AccountNum = @AccountNum;

...which isn't really the performance-critical bit 😛

Please do take the time to post the plan for the final SELECT - the cause of the slowness is almost certain to be obvious from it, thanks.

By the way...SET NOCOUNT OFF?

I think you would benefit from reading Erland Sommarskog's work on the subject: http://www.sommarskog.se/dyn-search-2005.html.

Paul