Mine is simply an opinion, but I would think you would continue feeding at any time the plant is in active growth. It will take it up if it wants it, and you will flush it out if doesn't.
A blooming plant is growing and expending energy to do so. Like any orchid generalizations, there are exceptions - some deciduous Dendrobiums, as well as Catasetinae, may bloom as they are going dormant so those you wouldn't. But for pretty much everything else, definitely keep up the fertilizing.
I've observed that when I fertilize my various hybrid mini catts when they have open blooms, the blooms seem to not last as long.
I'm not a heavy or particularly regular fertilizer, and usually only do so when there's active root growth, and when there are new shoots I'll use Peter's Cal Mag.