Two icons in different parts of an interface are intended to be recognized as representing the same thing at some level, yet are also distinguished by other visual cues (size, location within interface, some graphic details) as having differences of purpose. To describe them in claims as a comparison, is there a better phrase than 'substantially similar'?
The followings are not to be construed as legal advice or opinion.
If the two icons differ by look ('visual cues'), location ('in different parts of an interface') and purpose (a thing at 'different level', assuming your 'some' is not the typos error for 'same'), then I believe they are neither same, nor 'substantially same'.
One suggestion is to treat those two icons as different and claim construction (example) can be as follows:
a first icon to represent (say A) at (location) wherein the first icon (mention all characteristics)...
a second icon to represent (the A) at (location) wherein the second icon (mention all characteristics) ...
Again I repeat the golden rule, "go to a professional (patent agent or attorney)" for reliable and best advice.