It is still extremely early in the cycle - it runs through May. We're probably just getting past the first "wave" of IIs. You should not take this as a soft R; as far as I know, IU doesn't do soft rejections/ghost. If you look at some comments above yours, there are still several people who were verified early and still haven't gotten a receipt notification as well as others in your position (and I'm sure a lot of other people who just don't comment or don't visit SDN). Just my $0.02, I don't think you should send an LOI (not sure if you mean letter of interest or intent - either way, those are usually reserved for post-interview)