Another way of filling Nissan Plate?

Greetings.
I need to refill the automatic transmission in a Nissan Platina. I already know the different ways to refill an automatic transmission, but these cars are complicated and small, and I'd appreciate it if someone could give me specific information about this transmission.
It seems to have a plug on top, next to where the shift cable connects (which I've already identified and is mentioned in a manual I found here). The problem is that it's under the cable, and I need to remove the cable to access the plug. I noticed that right next to where the shift cable is screwed in, there's also a kind of flexible plastic tube (like a dipstick) with a cap that can be easily removed. It's also connected to the automatic transmission and appears to have oil markings on it. I can't find any mention of this tube in the service manual, but I assume it's also used for refilling the transmission. Can someone clear up my doubt as to whether this tube is for filling the transmission or if I'll have to remove the plug that's under the gear shift cable?