Saying Av Horachamim after Ashrei - Source, change?

Av Horachamim was first written after the crusades and the demolishing of the communities in Ashkenaz and France. Hazkoras Neshomos in general including the names of all of the people killed was done, next ashrei was said, and then came Av Horachamim, requesting God to remember the נאהבים ונעימים that were mentioned before. This was meant to be done twice a year, on the Shabbos before Shovu'os and the Shabbos before ט באב.
Later, in Poland, this tefilloh was shifted to be said all year around, and that is when (and where) it was moved to be before Ashrei.

Michael FRBSH

There is no problem of hefsek between Ashrei and Shmoneh Esrei of Musaf, and there is also no problem of hefsek before the Kaddish, since there are many psukim in Av Horachamim and in the Hachnoso, therefore there is a reason to say the Kaddish.

Minhag Ashkenaz to say Av Horachamim after Ashrei is brought in Arugas Habosem (Miba'alei Hatosfos), the Maharil, Minhogei Fuerth, Divrei Kehillos and many other sources. Minhag Polin is brought in Minhogei R' Isaac Tirna, the Levush, and the Mateh Ephraim. They do not give a reason for the change that was made.

It is interesting to note, that in the Baer Siddur (Avodas Yisro'el pg 233) he mentions saying Ashrei, and then mentions Av Horachamim, stating that Minhag Polin is to say it year around. It seems from him that in his days Minhag Polin said it after Ashrei as well.

Michael FRBSH

In Mincho there were no Psukim at Hachnoso, until about 200 years ago, therefore one could not say more than one Kaddish after Kri'as Hatoroh.

Michael FRBSH