Carlson BRX6+ to OPUS problems

I need some advice. I am trying to establish a base by doing a static session and converting my .BIN file to a Rinex3 file then sending it off to opus. Where I am having trouble is after I get it back from OPUS and enter in into my data logger then go check a NGS my horizontal is close (within 6") but my vertical has a fill of 6.62 FT. I am not sure where I am going wrong. I've made sure my base height is right, I converted my Base height from ft to M for Opus, My rover height is correct, I've tried to do another burn to see if I possibly got bad info from OPUS. I can't seem to get my height to line up with the NGS. And yes I have tried to check it on a different NGS and still same problem. Any suggestions? Thanks.