Comparable progress between Angel and Rainbow?

I am sorry to be a nervous nellie. Lost our Angel in Sept 2017 at almost 9 weeks. Had a chemical pregnancy in Feb 2017.

Just had second HCG on our Rainbow (5 weeks 6 days). I noticed the growth rate on this pregnancy is not as fast as the rate on the one we lost.

First on HCG on both was at about 4 weeks 6 days weeks from last period. Second on both HCG tests was a week later (Friday to Friday).

Angel

1st HCG 917

2nd HCG 7256

growth rate 7.91

Rainbow

1st HCG 1490

2nd HCG 9967

growth rate 6.69

Has anyone else compared this? Should we be worried?

Thanks