tacx Neo 2 accuracy

I'm sorry, but could you elaborate? Culd you give some insight into where the 10% difference occurs? I can only speak for what I see, and this is a linear phenomenon, so its 15W at 150W, and 30W at 300W, 

which is huge, one must be incorrect, 

Folano do You have any comparison chart? (dual analisys) what kind of bike power meter do You have? If You dont have such a chart, can You share 2 FIT files with the 2 power datas?

indoor rides i record always twice, one with my Edge 830 and one with a Trainer Software, the Trainer Software controls my Neo 2 and Edge is only reading the power of Vector 3 instead of Neo 2, so i can see the power difference live arround 10% difference, mean Neo 2 gives the lower value.

With Powermatch 2.0 of TrainerRoad i do the same, but Trainerroad is able to correct this difference, so during my rides i have the same power output on my Egde with Vector 3 and on TrainerRoad where Neo 2 and Vector 3 is paired together and Trainerroad gives the commands to Neo 2

It is great but if You have 10% diff. then your Neo2 or your pedals are wrong. The pedals could be verified with known weight. If those are right, then the Neo2 is faulty. Question, is it still in warranty or not.

both are in Warranty, but i won't wait weeks to get a replacement of Neo, i made this with Neo1 to Neo2 (i waited 2 month till it was confirmed, that my old Neo had probs), so i have no problem with it and don't forget the better values are the important ones 

So Powermatch 2.0 solves the prob for me, i don't need more!

this powermatch is working only with ERG mode, (it works in Zwift too, but just in ERG and in workout mode) but if You are in SIM mode, it doesnt. And if You wanna race in Zwift, the trend is You need to provide 2 power datas for transparency (the trainer's power must be the primary in Zwift, so You cant use your pedal's power there, just as a dual data on a head unit) but if You have 10% difference then the dual recording is not valid (because the difference is too high , the normal difference between rear wheel and crank is ~2% and +-1%, the tolerance limit +-6% as i know  there) and You will be DSQed. Lots of users wanna use his trainer for that so they need accurate measuring from trainer and from bike power meter too (and the bike power meters could be faulty too and could overreport the power , so the fact that You can buy a bikepowermeter with advertised accuracy that means nothing, there are many garbage bike powermeters on the market even on high price as "high-end" unit...)

I've had my Neo 2 for 18 months. It has always read 7-8% below my Assioma Duos and,  as far as I am able to judge, equally below my previous two Neo 1s. Yesterday I updated my Assioma firmware to the new auto calibration version and tried a comparison ride with the bike on the small ring and with a straight chain line.  Same story.  Neo 2 remains 7-8% below the pedals. 

This is data from a group ride yesterday on Zwift. I used slope mode from my 6X Pro Solar to enable me to stay in the small ring and maintain the straight chain. 

eezytiger how is your Assiomas connected to Zwift? via ANT+ or BT? if BT, the "Unified L" setting is enabled in Assioma app? 

this 13w avg difference at this power level is too high, so something is off. Did You validate your pedals with known weight? there are many cases where one of the pedal is reading more or less than the other (or both pedals are measuring more than they should) and makes the difference so high (or to negative difference as "drivetrain gain" )