Charging circuit - reduced load on ammeter circuit

Not always.
For examples you won't know of any high charging and overcharging.
Add a voltmeter and you may be wise to a high voltage situation, which would cause overcharging.
I'm not arguing....just asking/trying to learn here.
Let's say I run a hefty wire from the alternator to the battery. So I get used to how the ammeter reads after that. "WHY" would I not notice a change "either" way whether it's charge or discharge? I mean I'm used to how it works now. It works correctly. If I get used to how it reads with the new wire run, what will keep me from noticing a big change? I get that running the extra wire will reduce the ammeter's reading, but won't it still register "change"?