I took IB and AP in high school so hopefully I can shed some light on this subject. A 7 on an SL test and a 6 on HL are both fantastic scores that weigh about equally when taken into account that the 6 is for a higher level class. In account to an AP test - unfortunately a 7 isn't any better than a 5. So for example, your 7 (SL) and 6 (HL) would equate to about a 5 on an AP test of the same class subject. Furthermore, a 5-6 (SL) and a 5 (HL) would be about a 4 on an AP test.