Q. I have heard that in some congregations the most honoured place to be called to the Torah is Acharon, the last aliyah. Why is this?
Those called up in between would not say a b’rachah. Hence the person called up last had a special privilege.
Two other explanations are possible. The last person called up had the additional honour of rolling up the Torah and so he was doubly blessed.
In addition the final aliyah is the one through whom the Torah reading becomes complete.
By way of analogy, think of the rejoicing when on Simchat Torah we rejoice at the completion, not of merely one section, but of the whole Torah.