Actual or reat internet speed rates Mbps delivered as measured by Ookla.

Want to see if anybody had measured actual Mbps speeds delivered as measured by a third party like Ookla. We are on a purported 2 Gig plan supposedly having speeds up to 2 Gigs. Actually download speeds as measured by Ookla is 425 Mbps. Wonder if we drop to a 500 Mbps plan what would the actual download speed look like?