This indicator is almost same as the "normal" MACD, except that its values are normalized and are roughly falling into a predictable range of values (unlike the regular nacd, that does not have that predictability of expected ranges).  That makes it usable for direct value-to -value comparison over different instruments and / or timeframes (since the values are comparable now).

Even though the values are "very similar" to the original MACD, the values can differ significantly — see the example: lower is the "regular"MACD , and, as it is obvious, it is quite different in some periods of elevated volatility from the normalized version (not just regarding values, but the slope as well as the signal values).

It should be used using the same rules as regular MACD, but some experimenting is advised.