Is EBS DR Role Transition (switchover, failover, switchback) supported using fewer application serve

We are building a DR site for our R12.1.3 E-Business environment. Our team is recommending we mirror our production environment at the DR site but are meeting some resistance due to number of servers currently allocated for the DR site. Is this even a good decision to have only one appsTier considering the business plans to test/practice failover twice a year and possibly switch over more times per year? Is this even a recommended configuration?

Primary Location

dbTier

2 appsTiers

Load Balancer

Single sign-on

On the standby/DR Location

Standy

dbTier

1 appsTier

Load Balancer

Single sign-on

Thank you,

Melinda