יעמוד שישי

                Is last least?

It is customary when calling up the last speaker at a simcha or function to say  "אחרון אחרון חביב".

It is also customary to honour special people with ברכה אחריתא.

It's done so, as to suggest that this כיבוד is a חשובע כיבוד 

Is last, more of a כיבוד than the ones before?

The phrase אחרון אחרון חביב comes from Rashi in Parshas וישלח .

Yakov placed his family to stand in front of Eisav , in the order of his love for them. Hence, first the Shfochos & their children then Leah  & her children and אחרון אחרון חביב Rochel & Yosef. ( distanced farthest    from Eisav) They were placed there for greater protection and has  nothing to do with כבוד.

It is very likely that the last כיבוד is the least of the כיבודים and the  phrase is used, when calling up the last one, just to appease him for getting the last (least) כיבוד.

The Gemoro in Gittin 60a & Shulchan Aruch O.Ch. 136 lists whom to call up to the Torah after Kohen & Levi. The Gemoro says you start with the most חשובע person (Talmid Chacham& Parnes ) until you get to the last two עליות 

(שישי* & שביעי) where everyone can be עולה.  According to the Gemoro and

Shulchan Aruch , last עליות  are the least כיבוד.

The Mishna Verurah  (136 sk5) writes in the name of the Achronim , 

Today the Minhag Is for the Godol Hatzibur (The Rov etc.) to be mesayem

the sidrah  (takes Achron.)

There might be two reasons for this practice. a) אין המצוה נקראת אלא על מי שגומרה

b) The Rabonim who are עולה אחרון are practicing humility. (Praven Anivus)

For this reason שישי became a חשובע עליה. Being the Gemoro says that

From שישי and on everyone may be עולה, there were Rabonim who were humble

and asked to be called up for שישי . Eventually, it became the חשובע עליה to

be given to Rabonim.

*The Zohar disagrees with the Bavli and considers Shishi as a Chashuva Aliya.