It may be relative when comparing charts between trading platforms (trading activity can affect), but it will not have a significant difference.
-snip-
I tried different time frames to see if it's from the last candle close, that's not it.
What you say is correct according to the formula.
The Formula for the Price Rate of Change Indicator Is:
ROC = ((Closing Pricep − Closing Pricep−n) / Closing Pricep−n)×100
where:
Closing Pricep= Closing price of most recent period
Closing Pricep−n= Closing price n periods before most recent period
The price movement percentage is reset to 0% at the closing price (last close candle) every 24 hours (I don't know the exact time) and it applies globally. In my timezone, the percentage reset happens around 8 a.m.