Perhaps, I am misinterpreting your posting, but, the salary for the first year resident is usually lower than the second year resident. As a resident progresses through the residency, there should be an increase in the salary with each advancement.
As for salaries for residency, it is a very complicated subject. Each hospital usually set their own resident's salaries. The chances of DPM resident's salaries matching the DO/MD resident's salaries in the same hospital usually occur in the university hospitals or major teaching hospitals that have several residency programs. One reason why there is a huge range of salaries for Podiatry residents is that many Podiatry residency programs are established in smaller hospitals or non teaching hospitals that either have no MD/DO residency programs or maybe one MD/DO residency program. The resident's salaries in these smaller hospitals are usually lower than the major teaching or university hospitals. Of course, there are a few exceptions (such as some of the smaller hospitals in Michigan).