The increase should lower your blood pressure. I have been taking lisinonpril 20 mg for blood pressure going about 7 years. The recommended starting dosage of lisinopril for people with high blood pressure is 10 mg, taken once daily.
Your doctor may be increasing based on the blood pressure response and consideration to side effects of lisinopril, the dosage may be increased or decreased. For most people, the normal daily dose is 20 mg to 40 mg. For each change in your lisinopril dosage, it may take several weeks to see the full effects on blood pressure.
Hope this helps and your blood pressure is properly controlled without side effects. Thanks for the question.