If your girls are healthy there is no need to flush your pot.They in week 12 of flower on my estimation... This was a regular seed. Leafly show 9-10 weeks but I only take it as a estimation from them. Not to say that it must flower for that period of weeks. I would think that a regular seed flowers longer than fem seeds. I will let it flower a bit more till 90% of the pistils are amber.
Some nutrient lines recommend a flush it clean buildup around roots. If it is recommend then follow instructions, if not then feed as usual right up till you turn your lights off before harvest. You can not wash nutrients from your buds, scientific fact. Don't stave your ladies unnecessarily.