Good Day ohcanada15,
Interview is not a good thing since most people are scare of it. When you go through that way you have 50/50 chance to fail or pass and it stretches your application for a long time as it was suppose to be for a routine case.
Contact your MP for the date. What are the reasons for this interview? since you have your GCMS notes with you? It is very rare for CIC to reverse its decision once an interview has been called for because they feel the need to meeting the applicant and ask some valuable questions.
Yes it is normal if an application is lacking so much information or have a lot of inconsistencies even more if there is incompatibilities between SPR and PA, then an interview is recommended. Something is smelling fishy according to them that is why they want to see PA in person.
There are times whereby CIC can request a phone interview, this type of interview means that they don't have any problem with your file but just checking if what they have in the systems is correct. Most CIC's offices in North America, Europe, Australia and New Zealand do those calls since it is easy for them to contact the applicants.