I have heard of folks adding a small amount of the controlled release stuff, then supplementing with water soluble fertilizer but I am not a fan of those fertilizers.

Once they have gotten wet once, the rate at which they release their nutrients is determined entirely by temperature. Producers should provide a chart that tells you the "life span" for a given temperature, so if you have good control over the temperature of the potting medium, then you can do a good job of dosing; mixing a known mass of the formula into the potting medium, knowing it'll last "x" months.

Unfortunately, most folks just don't have that good of a control over the temperature, courtesy of seasons and changes in sunlight level, making the likelihood of overdoing it a real problem.

Orchids are, by far, very undemanding of fertilizer, and I think it just makes more sense (and we know how to control it) to simply apply a very low dose of fertilizer at every watering, flushing the daylights out of the plant with the solution each time.