If your cookies in same format as BAS, you just read it from file to variable and go Network-load cookies-set cookies for browser. If format of your cookies not compatible with BAS, compare and convert all your cookies in right format
Yes, i also faced this problem, what i did was if file size was > 100kb then i delete cookies and bot will check if cookies are not present then it will call login function and new cookies file will be saved which will be less than 100 kb.