Brother MFC 8480DN Scanner

I've had this scanner for several years with no problems, but recently (with the help of an off-site tech) changed the "print" function to tif from jpg.

Now, whenever I attempt to scan several documents at once into a single file, it picks up tif files that I've scanned in that same file previously and includes them in the current scan! And many of the pages intended for the current scan are missing!

Next problem - I deleted tif as an option because of the problems above and am now only doing jpg scanning. However, the jpg scanning only allows one page per scan, so a three-page document ends up as three separate jpg files.

Please help - this is driving me nuts! And the manual is useless.

THANK YOU IN ADVANCE TO ANYONE WHO CAN HELP ME!!!!!