Hi,
the way your etherchannel is configured is right, it is not a good idea to use the ports in etherchannel on the same blade. With the ports distributed across different blades you have more resilience than in just one blade. If one of the blades that you have the etherchannel ports fail, the other ports will remain working fine, which guarantees that your portchannel link will be up even in a problem with one blade.
Regards.