ME909s-120 problem with usb-modeswitch and huawei_cdc_ncm

Installing and Using OpenWrt
1

I have recently got a M909s-120 (12d1:15c1) and put it in ZBT-WE1326.

First problem was the one explained here https://bugs.openwrt.org/index.php?do=details&task_id=1424

I somewhat fixed the problem by changing the /etc/usb-mode.json file by setting

                "12d1:15c1": {
                        "*": {
                                "mode": "Huawei",
                                "msg": [  ]
                        }
                },

Anyway, now it loads cdc_ether module and it appears as usb0 interface and I am able to connect to internet with NDISUP...

I have some questions:

1- Why this card is not recognized properly and I had to change the usbmode config file? Am I doing something wrong?

2- Shouldn't I be able to use huawei_cdc_ncm ? or perhaps cdc_ncm? I found at least one post where somebody says ncm works? Mini PCIe LTE modem recommendation

What about mbim?

3- Is there performance penalty for using cdc_ether?