According to the IBEX Principal Investigator, you have it backwards. From [link to www.ibex.swri.edu]
"...That difference in speed, about 7,000 miles per hour (11,000 kilometers per hour), does not sound like much but it means that there is about 25% less pressure in the region in front of our heliosphere. What this also means is that there is not the right combination of density, speed, pressure, and magnetism to cause a bow shock to form....Our heliosphere is like a protective cocoon being inflated in the interstellar medium by the Sun’s million mph solar wind. As our Sun orbits the center of the galaxy every couple hundred million years, it bobs in and out of the disk of the galaxy like a horse on a merry–go–round. As it does this, it passes through areas of the interstellar medium that are more and less dense, causing the heliosphere to change in shape and size. Denser areas with larger speeds relative to the Sun can compress the heliosphere more, while slower and less dense regions allow the bubble to expand..."

We are in a slower, less dense area than previously thought. Hence, no Bow Shock, just a Bow Wave. Less pressure means the heliosphere should expand, as per the article.
[link to www.ibex.swri.edu]