I would think any detritus removal is better than not at all, so it would help, and if you gave the water 10-15 minutes to settle, I'm sure you'd help a great deal.
Some of my BB siphoning techniques are:
My 33gallon long sump only has a mag7 as a return, so the flow through it is pretty calm. In the middle of the sump I have a settling area of about 24-30" (never measured it,
http://www.d3f.org/misc/fish/90g/04-sump.jpg). The water is calm here and any heavier particles that didnt get removed by my PS in the previous compartment are brought here and settle out of the current, before it is returned to the tank.
This settling area (and my skimmer efficiency) was GREATLY improved after I added a second Seio 1500 (Previous had 2x1100 and 1x1500). This extra flow and re-structuring of rock (so they arent sitting flat on the bottom, but on points) brought more detritus down from my display into my sump.
Once in this settled area, I perform a 5 gallon water change 1-2 times a week to remove it.
The second technique I use for siphoning includes a 150micron bag and a long 1/3" vinyl tube. I attach the bag with a ziptie to the end of the hose, place that end in the skimmer compartment, then start a siphon from the display tank. Here I tackle the 2 areas in my tank where detritus slowly accumulates. I've only just begun to do this, but I dont think it will be needed more than 2x a month.
The final technique is using my oversized algae cleaning magnet to stir up the tank even more. I will race it by the glass in certain areas and stir up even more current / alternating currents that current exist. This will kick up more matter which finds its way into my sump/PS. I do this casually when I clean the glass (once a week). Combined with this is grabbing a powerhead and just aiming it at different parts of the tank to kick up anything I may have missed.
