It's possible your deletes are registered instantly, but the cache of information that serves those functions were not wiped until the existing cache expired five minutes later.
I'm not talking about deletes becoming "visible" on the timeline after a delay, I mean that the browser is completely blocked and unresponsive for 4-5 seconds (not minutes!). That makes deleting by hand lots of posts and likes a total PITA.
Could be, or could it be something that seethe user-agent and the influx of deletes from a tool as a denial of service and intentionally throttles responses?