I look at Elliott waves, and estimate where prices might climb at the tops of waves 3 & 5. I use the weekly Stockcharts, and record the lows and highs over time. It looks to me that occasionally, these weekly prices change. Am I nuts, or are they updated or do they change over time? Thanks,

I’m not sure I fully understand your question fully. Can you rephrase it?

Sorry, Sean ... after recording (on a spreadsheet) weekly lows and highs for specific stocks or ETF, and calculating estimate future price targets, often, the highs and lows that I have recorded ... change from the previous time I recorded them.

Is this to be expected on occasion, as corrections?

A weekly candle is only closed/completed after the market closes on Friday (after 4pm EST).

Makes perfect sense, thanks Sean