Okay Sir,
Following up with your case, we need to distinguish between two different issues. Primarily, the balances of your inventory items and whether it is showing properly with no contradictions among IV inquiries, reports and Smart List. The script above shall calculate your inventory balance and compare it with the master balance, in case of any variances, it shall be distinguished. What I see above in your print screen, all the shown variances are zero, in case you have any records with no zero variances, please share to dig for further details.
As for the decimals, I can add nothing more valuable to what's mentioned by Ms. Leslie, you do have a problem and I am absolutely sure that you may have other third party product entering some sort of transactions into your inventory, or some sort of back-end modifications have been applied on your db.
Let's split the overall problem into pieces, that would really help all of us reach a happy ending.
Your feedback is highly appreciated,