Hi sherxon,
Many Business Schools have publicly stated that they do not use an applicant's IR score when evaluating an application, so you likely have nothing to be concerned about with an IR5 (and retesting is likely NOT necessary). However, if you're interested in what a specific School/Program thinks about the IR score, then you should research that School directly (you might also consider contacting the School to ask).
In addition, assuming that you are interested in some highly-competitive Schools, then you would likely find it beneficial to speak with an Admissions Expert about your overall profile and plans. Those Experts should be able to answer your Admissions questions and help define the specific areas of your profile that could use some improvement. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/GMAT assassins aren't born, they're made,
Rich