is it soilless? Yes, it is important.
And stop doing wahtever it is you think a "1/4" dose feed is.. sounds like incomplete irrigation to me. This will train roots to grow superficially as they turn toward greater moisture at the top due to the ncomplete irrigation. Watering is simple. Don't overthink it.
1) fully saturate with10% runoff (in soilless). If in soil, a minimal runoff barring any leaf symptoms is fine. This is so you don't leach off all those amendments you paid for in the soil, but you still want the entire thing to get wet. This is not "overwatering"
2) wait for appropriate loss of wait or 'dryback' -- not really about drying and more about the plant drinking.
Rinse and repeat...
If you get any droop, that is indicative of a poorly constituted substrate and nothing else... shouldn't see droop unless running a shit ton of water through th esubstrate and drowning the roots for 5-10 minutes or more. (not referring to a slow drip that takes 10-15mins to complete the task -- limits compaction doing this. this is not a large volume of water, just slow)
If making it more complicated that that, it's probably more about OCD-type behaviour than any benefit from it.
in soil if you run into a buildup in the substrate, extra runoff can help dilute that, but it's a reaction to a problem observed and not just done randomly. Flushing is stressful and slows the plant down, so tehre should be a good reason to do it. You paid for that soil, so you should minimize washing the nutrients down the drain that came with it.
Promix Bx is essentially soiless after 5-7 days. It does come with a basic pre-charge of nutes around 1EC. A plant will exhaust that very fast. I use BX or HP - whichever is cheaper at the moment, but also add enougghvermiculite to bring the sphagnum peat moss to perlite+vermiculite to 50/50 (or 1:1, whichver you prefer). This is results in a better gas:water mix.
Youou should rarely have to flush with a soilless growing method. That means you aren't adjustingn your formula based on what the plants tell you and overfeeding them for long periods of time. The 10% runoff maintains a consistent resulting EC of nutesin your substrate. This consistency is the primary benefit of soilless along with the nutes being 100% available to the plant the moment they are added. Any symptom seen is 100% caused by your formula and nothing else. (assumes it is ph-balaced. that should be common sense). This eliminates a multitude of other potential cuases to any symptom seen - making diagnosis an dfixing the problem easier -- plus, you should be able to avoid that particular problem in the future with a more optimized formula going forward.
keep nutes of not only concentration given but also ratio of each nute.. or elemental ppm of each.. fertiization is a culmination of everything you've done since it was planted, and not just last night or last week.