no. if you go with two low size dimms and find out you need more ram for your pc you have to sell or toss those dimms to add two larger dimms. your better off with two slots to go with one eight gig dimm then when you have the funds add the other 8g dimm.
Go with 2 x 4gb particularly if you use integrated graphics which will depend on ram performance.
Likely worth the $10 delta.
smorizio has a point, but there is another possible issue with adding ram.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
The internal workings are designed for the capacity of the kit.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, can be very sensitive to this.
This is more difficult when more sticks are involved.
That is why ram vendors will NOT support ram that is not bought in one kit.
If you do buy more disparate sticks, they must be the same speed, voltage and cas numbers.
Even then your chances of working are less than 100%
What is your plan "B" if the new stick/s do not work?
If you plan on more ram, buy a 2 x 8gb kit up front or plan on replacing the initial 2 x 4gb entirely later when you need to.