Is anyone else finding this combined heat island credit much easier to get than expected?  Given that the thresholds were raised for non-roof paving SR, I understood that additives to lighten concrete would most often be necessary.  With the weighted area calculation we are finding projects with normal grey concrete and 100% high SRI roofs are earning the credit in spades.  This is because the weighted area of qualifying high-reflective roof reflects the extra roof area beyond 75% and the SRI value above 78, giving projects credit for 10% to 15% more roof area.  Meanwhile, the .26 initial SR value of grey concrete still contributes but a discounted rate that is about 15%-20% reduction of the total area.  I like that this methodology is more performance oriented, allowing projects to trade off areas and get partial credit for the reflective properties materials have, even if they don't meet the threshold, but it is not driving projects to change much.  Only one of these projects has been through design review so far so I thought I'd get some LEED User feedback on your experiences.  Thanks in advance for your thoughts.