I know I'm late to this conversation, but we go with an even simpler solution. I've trained our PM's to just change the Planned Hours to the new total (including what's already been spent). In this example, change the Planned Hours to 52. And if the task planned completion will be extended due to this, be sure to change the Duration (not the Planned Completion Date). This way you retain your Start Date and the planned hours are still spread across the proper dates (or at least close). The downside is losing the original estimate but if you really want that you can use the Baseline to obtain that. Honestly, we've never gone back to check the original estimates at a task level. Heck we barely do it at a project level yet

. Perhaps that all speaks to our Project Management Maturity level but that's how we do it and it's good enough for our purposes at this time. Hope you find what works for you.