Thanks for asking a question at health care magic.
The blood pressure in the body is kept in a delicate balance by our sympathetic and parasympathetic nerve
supply. Any anxiousness or stress
is bound to increase the BP to some extent. Your both the readings of 138/80 and 130/78 are quite with in normal limit and that you shouldn't worry. Secondly there could be some manual and instrumental errors also to cause such changes in the measurements.
You can be comfortable with both the readings.
Hops I am able to solve your concerns.
Thanks. have a nice day!