Using a different sequence means putting things in a different order. Here, you’ve used different forms of verbs in the same tense — the present tense.why are you saying that the sequence of tenses is the same?
1 Present Perfect Continuous + Present Perfect Continuous
2 Present Perfect Continuous + Present Simple
I'm not entirely sure I understand what you're asking here, but just looking at the tenses...1) "I started (to start) learning English at school in Switzerland when I was eleven*, so I have been learning (to learn) it nearly for ten years."
According of the keys (and I quite agree with them) the underlined grammar forms are the right answers here. But in this case I have some doubts concerning the second part of this sentence. The independent or principal clause in the sentence is "I started learning English at school in Switzerland", so all the the parts of this very sentence should follow the rules of the sequence of tenses. In this case why do we put "so I have been learning it nearly for ten years" here? Of course, while taking independently, we can't but point out the special grammar indicators of Present Perfect Continuous, "showing" us that the process of learning English is still in progress, - "for ten years". But what about the first and main part of the sentence that is written in Past Simple?