Smoothing of servo PWM - take different loop() speeds into account

[falue]

TX sends:
95,100,105,110
-> one integer per 30ms/loop(), but the RX receives each 2ms/loop():
95,95,95,95,100,100,100,100,100,100,105,105,105,105,105,110,110,110,110
-> this will be interpolated as
98,98,98,100,100,100,100,100,103,105,105,105,105,108,108,108
(small steep curves, stair like result) instead of a big curve:
97,98,99,101,102,103,104,105,106,107,108,109110

Solution:
loop of TX takes around 30ms, loop of RX only around 2ms.
either:

• add ~28ms delay in TX loop (poor choice)
  or
• only interpolate values every 15 loops() fo the RX
  or
• only interpolate values when the oldValue != currentValue
  or
• use time-insensitive smoothing function

[falue]

or:

if(millis() % 30 <= 5) {
  currentSmoothedX = exponentialMovingAverage(X, smoothedValueX, smoothingX);
}