I don’t use bumblebee so I can’t weigh in from memory here (most all my posts are from my phone while on the train to/from work). I can share some of my process as a possible work around for you.
I do must of my excel work with the native nodes and use other pre-formatted sheets and built in excel references to do my formatting. I have a ‘template’ marked read only with two sheets in it. First sheet is the ‘raw’ location where I write my data from the model, this gets overwritten when I run the script. Second sheet is the formatted sheet which reads the data off the raw sheet and sorts/formats/whatever else.
When I run my script the first step copies the template excel file to a new location, writes to the ‘raw’ sheet and have the ‘formatted’ sheet report the right stuff every time.
Hope it helps.