Akaline Fixer after KFeCn Bleaching?

Heretofor, I have alway use a solution of hypo periodically after bleaching. Does anyone know if the hypo can be sustituted with an alkaline fixer?

The main purpose of the hypo is to stop the bleaching process. The bleach will contaminate the hypo and the used bath should not be used again. Since plain hypo is cheaper than alkaline fixer why would you want to substitute.