The studies consider only continuing expenses, not front- or back-end loads.
It's similar to a back-end load in that no sales charges are paid when buying the fund.
Instead a back-end load may be charged if the shares purchased are sold within a given time frame.
They will pay back-end loads generally starting at 5 or 6 percent and declining one percentage point a year until gone.
The B shares are sold without an initial sales charge, but have a back-end load and a higher 12b-1 fee.
Some funds have a back-end load, which is paid by the investor when shares are redeemed.
A back-end load is determined by how long you keep your investment.
There are various types of back-end loads, including some which decrease and eventually disappear over time.
This can mean that there is no front- or back-end load.
Note that the study did not even consider front- or back-end loads, or sales charges.