When I re-read the PureOne advertising materials it was not totally clear to me if the "13 grams" reference actually represents the PureOne oil filter's maximum filtration capacity. However, you may be right concluding that the new synthetic line of oil filters may be designed to capture and hold more contaminants, albeit of those a larger size @ 25 microns vs. 20 microns for PureOne filters. It's also not clear to me if the 99% filter efficiency rating for the synthetic filters was based on the larger 25 micron particle size.
The new synthetic oil filters appear to be positioned to appeal to those who prefer to use synthetic motor oils and who want to use extended drain intervals accordingly vs. the PureOne filters which have been promoted as premium oil filters which provide a near-perfect (99.9%) level of filtration efficiency. Note that for extended drain intervals some manufacturers have recommended that their oil filters be changed every 5k miles, or ~ 1/2 way thorough a 10k-mile oil change interval.
Note that filtration "efficiency" ratings promoted for the 3 Purolator oil filter lines are listed on their website as follows:
L "classic" filters: 97.5% @ 20 microns
S "synthetic" filters: 99% @ 25 microns (?)
PL "PureOne" filters: 99.9% @ 20 microns