Personally I find this input to give inaccurate calculations. But back to the question. After you input the W/V on Perf page it will 'soft' input this W/V for the whole flight on all sectors. (I can't see why this should not be a quite accurate for fuel prediction and ETA if the the route average W/V is inserted.) I don't see much point in inserting TOC W/V. It is highly unlikely to get a continuous climb to FMC CRZ FL. Later you can insert RTE DATA W/V. This should give an accurate ETA, but I find it's not so good. When in CRZ the FMC prediction for current WPT & next WPT is made using actual wind. There after ETA & Fuel at destination uses RTE DATA W/V. That's what I've always been told.