hi please contact [support@jlcpcb.com](mailto:support@jlcpcb.com) they will tell you thanks

@gamerpaddy, By adding vias, you are reducing the area of copper within a track on a layer. Even if you use vias to connect to tracks on other layers then you are then reducing the area of copper available on each layers. Adding lots of vias only works for high current tracks if you have a large area of copper compared to the area removed by the vias themselves and then only if you cluster the vias at the start and end points of the tracks. Adding vias is good for reducing resistance and inductance when connecting tracks and pads to planes and so increasing current capacity between the layers but it is not so good for increasing the current carrying capacity of a track on a layer. For that you need more copper. You can increase the copper by making the tracks wider and/or thicker. You can make them thicker by specifying a heavier copper weight or by adding solder mask to expose the copper track so that it will be tinned or you can solder copper wire along it.

@andyfierman the wide tracks are double sided, connected trough vias and soldermask removed for tinning. goal is 30A and more on 1oz copper. @usersupport thanks i contacted them