Alexseal Metallic Paints

It will hold up as well as any other color that Alexseal offers. Alexseal Metallic Systems is a base coat clear coat system that utilizes an acrylic urethane as a base coat and a high solids aliphatic clear on top for excellent hardness and UV protection.
You can't go wrong with this system. Repairing a metallic color is more problematic than repairing a solid color due to the metallic particles or flop in the pigment. Metallic's will also be slightly different in color and appearance between spraying of vertical and horizontal panels due to how the particles lay & flow in the coating so this is always something to keep in mind if you remove a door or boarding gate and lay it flat to spray. It wont match the fixed vertical panel next to it when re-installed.

I remember shooting a car and loose trim parts with metal Imron. Candy red & flake and the owner didn't notice. Whooie.
Luckily I parted from body shop work during the late 70s.
I doubt anybody remembers lead filler before Bondo.

Empirical data shows that metallic panel matching is more of a wet film thickness issue versus an applicators cross coat technique. All high solids coating require the applicator to employ a cross coat gun sweep while shooting product and its called for due to maximum coverage in a short duration for shorter flash times of the product. Data shows that horizontal surfaces tend to collect paint quicker than vertical panels due to the laws of gravity & the applicators concerns over sags or curtains on the vertical.Horizontal surfaces will always have a thicker WFT when measured on the surface on a completed show coat. Alexseal Metallic Systems calls for an average of 5 mils WFT and 2 mils Dry film thickness for best results when utilizing their product so lets use A/S Metallic color of Anniversary Silver as a test for this theory. When the horizontal WFT is higher than the vertical WFT, the amounts of metallic's increase in the pigment applied causing the horizontal panel to be a shade darker than the vertical and many times will look like the next paint chip on the card this time being Snowpack Silver. BTW, Alexseal is the only company that actually utilizes paint on their color chip charts in lieu of ink as representation of true color so what you see on the chart will match what's on your boat if mixed and applied correctly. As far as durability goes, Alexseal Metallic's base coat has the same life span as Awl Craft 2000 as both technical data sheets are very similar & its the same basic Acrylic urethane that every applicator has come to love for its ease of application. What makes Alexseal's system last as long as any HPLP urethane is the hard as nails high solids aliphatic LP clear coat that goes on top. Yrs past metallic's that were produced by Dupont in their epoxy based Imron line were not overly UV resistant and would chaulk after a couple yrs sun exposure. Times and chemistry have changed as modern high performance linear aliphatic polyester polyurethane paints have excellent durability, hardness and UV protection from the old epoxies of 20-30 yrs ago. Also, equipment has changed rapidly the last few yrs. and the European applicators have been leaders in testing and utilization of the new spray equipment. HVLP guns are quickly being replaced by hybrid electrostatic guns and now fully aerated pressure pots with airless spray systems are the norm for superyacht painting reducing overspray issues and airborne VOC's while producing a beautiful finish

No such thing required. Alexseal RECOMMENDS waxing two to three times a year but this can be reduced to once every two years with the use of a ceramic polymer sealer. Awl Craft also recommends that you wax blends or dull spots where fenders have scuffed or hazed the outer layers of the coating. Any coatings manufacturer would wish for customer applied sacrificial wax or sealer coats on top of their product to ensure the base color is protected and its longevity increased through this process. Its easy to get into a huge debate about wax vs no wax on polyester urethanes & acrylic urethanes as forum boards are chock full of this debate but the only fast rule is not to high speed cut and polish a linear urethane. Acrylic urethane ( AC-2000) no problem in doing this if you need to but once you do this you'll be cutting and buffing every yr. to keep any DOI.
By sealing or waxing any type of top coat your providing a sacrificial barrier on top of your paint to prolong its longevity and luster. As far as a S/F brow needing a re-spray after 3 yrs I would venter a guess that the product used was Alexseal's G series system paint and not the newer HS- M system.