Maria,
I'm not aware of their being any consequences of having the values of GR and IR being different...
But if the GR has an incorrect value, that can lead to other issues. When you post a GR, there's a material document (recording information about quantities and material numbers) and a financial document (recording the account postings). For a standard-priced material, the financial document shows a posting to your stock account based on quantity received and the standard price. If the PO was not at standard price, the difference is posted to a PPV account, which companies like to analyze. It may be that your PPV postings are now wrong.
I'd try to find out how your GR values got to be incorrect: where did the numbers come from, document by document? What's the quantity and the price used to get a valuation? And I suggested reversing them individually, resetting the PO price as you do it.
I'm sorry that I don't have a quick fix for this.
- Jeff