Any chance they supplied you with OPKs instead of HPTs? OPKs are usually cheaper than HPTs.

I had a similar experience to TeniBear with my last BFP - didn't get a (very faint) BFP on the ICs until 13dpo and by that stage the FRER was clear as day. I was disappointed by the lack of sensitivity of the tests. I buy a different brand now, but haven't had another BFP to test them on... *sigh*