Is the consumption of armour and weapons based on the division setting or is it based on a percentage of what is actually equipped?

For example, 150 humans set to 8/8 plate armour requires 1,200 plate armour to equip and 120 per year to maintain. Whereas 150 humans set to 4/8 plate armour costs 600 plate armour and 60 to maintain per year. However, if I only have 600 plate armour to supply a division set to 8/8 on plate armour, will my army still consume 120 plate armour per year (even though it doesn't have 1,200 plate armour equipped) or will it only consume 60 (so 10% of whatever is actually equipped)?

In essence, if I only have 600 plate armour in storage and my city can only produce 60 plate armour per year am I worse off by setting my armies to 8/8 armour rather than the 4/8 setting that my city can theoretically support?

Thanks.