Changing Metrics in EIGRP for Reliable Transport
Whenever you are trying to change the path EIGRP chooses between two routers, it is best to change the delay metrics along the path rather than the bandwidth metrics. The primary reason for this is that the bandwidth configured on the interface affects the operation of EIGRP's reliable transport mechanism.
Using the bandwidth statements to influence routing decisions can have unintended consequences because the installation of a new link can unexpectedly override your bandwidth configuration. The delay metrics are cumulative; so, their effect is more predictable and manageable in the long run.