Attack move and factory attack move have different reclaim radiuses. When engineers reclaim with an attack move order that comes directly from the factory, they reclaim in a much larger radius without moving than they can with a regular attack move order or with manual reclaim. This extra radius makes reclaiming with factory attack move superior to reclaiming with regular attack move and patrol if you can keep the factory attack move order 'alive' (by moving it around the map and not letting your mass storage get close to full). This is because reclaiming in place with a large radius is a lot more efficient than moving around to reclaim with a small radius.
This extra reclaim range provided by a factory attack move order is presumably a bug/exploit that the original developers of fa wouldn't have intended. It makes the game harder for noobs, who generally wouldn't know about its extra range, and would thereby be at a disadvantage. It also steepens the learning curve in an unintuitive way.
This problem is further exacerbated by the unintuitive fact that factory attack move orders generally end when the player's mass storage becomes nearly full. So, if a player accidentally briefly has a full mass bar, it can create a large disadvantage if they were taking advantage of this factory attack move exploit. I've actually seen 1.4k+ players tell their teammates not to gift them mass and actually quit games over being gifted mass by a teammate because it cancelled all of their factory attack move orders. (Once a factory attack move order is cancelled that way, a player would normally replace it with a regular attack move order, which would generally be notably less efficient.)
This is not a desirable situation. I acknowledge that this exploit has been in the game for such a long time that some people think of it as a feature, but it's very unintuitive, it steepens the learning curve, it creates a bizarre situation where players are punished extra for having nearly full mass storage (even when gifted by a teammate), and it puts players who don't know about it at an unfair disadvantage. To give perspective, I imagine that somewhere between 30% and 99% of FAF players don't properly know about the factory attack move exploit or don't even know about it at all (especially the latter). This disparity can easily be observed by looking at the reclaim behavior and quantity in a generic pro setons game (pro setons players are some of the most likely people to know about and exploit factory attack move) vs a generic noob setons game (noobs are generally unlikely to even know about the factory attack move exploit).
I propose that this exploit be fixed by making factory attack move and regular attack move have the same radius/range. This could take the form of:
(1) the factory attack move range being decreased to the regular reclaim range
(2) the regular attack move range being increased to the factory attack move range
(3) both the factory attack move range and the regular attack move range being changed to be the same value that is somewhere in between their current ranges
Personally, I think (1) would be preferable as it would not give attack move/factory attack move an nonsensical reclaim range advantage over patrol and manual reclaim. However, I think any of those 3 solutions would be better than the current situation.
Some additional things that could make reclaiming more intuitive:
(1) make it so attack move orders don't end when a player's mass storage is nearly full - I think it would be more intuitive if the order basically paused its reclaiming (either when the player's storage is nearly full, or when the whole team's storage is nearly full) and then continued once the storage was less full
(2) make it so engineers don't break trees/tree groups when they walk - this would make patrolling a more viable reclaim option (as engineers breaking trees/tree groups is generally considered a disadvantage of patrolling due to the efficiency loss when reclaiming trees that get broken by patrolling engineers) and would also help reduce toxicity (people often get mad at teammates over breaking their trees with engineers on accident)
These solutions would fix an exploit, make reclaiming more intuitive, reduce 'hidden' disadvantages for new players, help reduce toxicity, and help reduce the game's steep learning curve. We're not playing a game of Mao here; we shouldn't keep convoluted and counterintuitive exploits that are basically 'hidden in plain sight'. I imagine there are literally hundreds to thousands of FAF players with hundreds to thousands of games each who don't know about this exploit and or don't know how to use it. This is a ridiculous situation.