DBCC CHECKDB running longer
There's a strong possibility that CU 4 for SP2 which was release in January of 2015 will resolve the issue you are experiencing: https://support.microsoft.com/en-us/help/3029825/fix-dbcc-checkdb-checktable-command-may-take-longer-in-sql-server-2012

That being said, you are running a SQL server that is out of support and SP2 CU 4 which should resolve the issue is out of support as well. You should go ahead and patch the server to the current SP4 CU 10 + the latest security updates.

It appears to me that you may also be running an old version of OLAs scripts based on the way you are calling them. They should be updated as well.