Fundal height help!

Has anyone been in to their OB practice and had their fundal height measured by different Drs or nurses and been told different measurements? I went two weeks ago and my fundal height was 26cms at 24weeks6days, I went again at 26weeks5days and I was measured by someone else who told me my fundal height was 25cms, is it even possible for it to shrink?! They said they would measure again in 2 weeks to keep an eye on it, but it seems odd to me!