[Android Software/Hacking General [Developers Only]] MrBlackbriar:
Hm, I don't know if this helps anybody at all, but I've been running the monitor-script in the Seeder_v6 package and played with my phone a bit (homescreen scrolling, Chrome, Subway Surfer), and I do notice drops in entropy_avail. (Seeder is OFF).

entropy_avail has gone up.. [ 170 ] : total [ 170 ]
entropy_avail has gone up.. [ 1 ] : total [ 171 ]
entropy_avail has gone up.. [ 1 ] : total [ 172 ]
entropy_avail has gone up.. [ 1 ] : total [ 173 ]
entropy_avail has gone up.. [ 28 ] : total [ 201 ]
entropy_avail has gone up.. [ 2 ] : total [ 203 ]
entropy_avail has gone down [ 72 ] : total [ 131 ]
entropy_avail has gone up.. [ 1 ] : total [ 132 ]
entropy_avail has gone up.. [ 1 ] : total [ 133 ]
entropy_avail has gone up.. [ 2 ] : total [ 135 ]
entropy_avail has gone up.. [ 9 ] : total [ 144 ]
entropy_avail has gone up.. [ 48 ] : total [ 192 ]
entropy_avail has gone up.. [ 66 ] : total [ 258 ]
entropy_avail has gone up.. [ 54 ] : total [ 312 ]
entropy_avail has gone up.. [ 66 ] : total [ 378 ]
entropy_avail has gone up.. [ 10 ] : total [ 388 ]
entropy_avail has gone down [ 161 ] : total [ 227 ]
entropy_avail has gone up.. [ 28 ] : total [ 255 ]
entropy_avail has gone up.. [ 79 ] : total [ 334 ]
entropy_avail has gone up.. [ 81 ] : total [ 415 ]
entropy_avail has gone up.. [ 106 ] : total [ 521 ]
entropy_avail has gone up.. [ 31 ] : total [ 552 ]
entropy_avail has gone down [ 197 ] : total [ 355 ]
entropy_avail has gone down [ 156 ] : total [ 199 ]
entropy_avail has gone up.. [ 3 ] : total [ 202 ]
entropy_avail has gone up.. [ 125 ] : total [ 327 ]
entropy_avail has gone up.. [ 60 ] : total [ 387 ]
entropy_avail has gone down [ 132 ] : total [ 255 ]
entropy_avail has gone down [ 123 ] : total [ 132 ]
entropy_avail has gone up.. [ 21 ] : total [ 153 ]
entropy_avail has gone up.. [ 94 ] : total [ 247 ]
entropy_avail has gone up.. [ 134 ] : total [ 381 ]
entropy_avail has gone down [ 80 ] : total [ 301 ]
entropy_avail has gone up.. [ 94 ] : total [ 395 ]
entropy_avail has gone down [ 137 ] : total [ 258 ]
entropy_avail has gone down [ 41 ] : total [ 217 ]
entropy_avail has gone up.. [ 70 ] : total [ 287 ]
entropy_avail has gone down [ 55 ] : total [ 232 ]
entropy_avail has gone up.. [ 129 ] : total [ 361 ]
entropy_avail has gone up.. [ 139 ] : total [ 500 ]
entropy_avail has gone up.. [ 144 ] : total [ 644 ]
entropy_avail has gone up.. [ 89 ] : total [ 733 ]
entropy_avail has gone down [ 53 ] : total [ 680 ]
entropy_avail has gone up.. [ 55 ] : total [ 735 ]
entropy_avail has gone up.. [ 42 ] : total [ 777 ]
entropy_avail has gone up.. [ 55 ] : total [ 832 ]
entropy_avail has gone up.. [ 33 ] : total [ 865 ]
entropy_avail has gone down [ 151 ] : total [ 714 ]
entropy_avail has gone up.. [ 67 ] : total [ 781 ]
entropy_avail has gone up.. [ 53 ] : total [ 834 ]
entropy_avail has gone up.. [ 26 ] : total [ 860 ]
entropy_avail has gone up.. [ 43 ] : total [ 903 ]
entropy_avail has gone down [ 94 ] : total [ 809 ]
entropy_avail has gone up.. [ 26 ] : total [ 835 ]
entropy_avail has gone up.. [ 48 ] : total [ 883 ]
entropy_avail has gone up.. [ 47 ] : total [ 930 ]
entropy_avail has gone up.. [ 53 ] : total [ 983 ]
entropy_avail has gone down [ 138 ] : total [ 845 ]
entropy_avail has gone up.. [ 119 ] : total [ 964 ]
entropy_avail has gone up.. [ 77 ] : total [ 1041 ]
entropy_avail has gone up.. [ 77 ] : total [ 1118 ]
entropy_avail has gone down [ 943 ] : total [ 175 ]
entropy_avail has gone down [ 14 ] : total [ 161 ]
entropy_avail has gone up.. [ 70 ] : total [ 231 ]
entropy_avail has gone up.. [ 71 ] : total [ 302 ]
entropy_avail has gone down [ 121 ] : total [ 181 ]
entropy_avail has gone up.. [ 51 ] : total [ 232 ]
entropy_avail has gone down [ 47 ] : total [ 185 ]
entropy_avail has gone down [ 7 ] : total [ 178 ]
entropy_avail has gone down [ 7 ] : total [ 171 ]
entropy_avail has gone up.. [ 35 ] : total [ 206 ]
entropy_avail has gone up.. [ 40 ] : total [ 246 ]
entropy_avail has gone down [ 77 ] : total [ 169 ]
entropy_avail has gone up.. [ 60 ] : total [ 229 ]
entropy_avail has gone up.. [ 57 ] : total [ 286 ]
entropy_avail has gone up.. [ 43 ] : total [ 329 ]
entropy_avail has gone up.. [ 44 ] : total [ 373 ]
entropy_avail has gone down [ 143 ] : total [ 230 ]
entropy_avail has gone up.. [ 34 ] : total [ 264 ]
entropy_avail has gone up.. [ 37 ] : total [ 301 ]
entropy_avail has gone up.. [ 50 ] : total [ 351 ]
entropy_avail has gone down [ 72 ] : total [ 279 ]
entropy_avail has gone up.. [ 51 ] : total [ 330 ]
entropy_avail has gone up.. [ 40 ] : total [ 370 ]
entropy_avail has gone up.. [ 41 ] : total [ 411 ]
entropy_avail has gone up.. [ 31 ] : total [ 442 ]
entropy_avail has gone down [ 165 ] : total [ 277 ]
entropy_avail has gone up.. [ 37 ] : total [ 314 ]
entropy_avail has gone up.. [ 40 ] : total [ 354 ]
entropy_avail has gone up.. [ 45 ] : total [ 399 ]
entropy_avail has gone down [ 252 ] : total [ 147 ]
entropy_avail has gone up.. [ 36 ] : total [ 183 ]
entropy_avail has gone up.. [ 4 ] : total [ 187 ]
entropy_avail has gone up.. [ 50 ] : total [ 237 ]
entropy_avail has gone up.. [ 65 ] : total [ 302 ]
entropy_avail has gone up.. [ 36 ] : total [ 338 ]
entropy_avail has gone down [ 120 ] : total [ 218 ]
entropy_avail has gone up.. [ 28 ] : total [ 246 ]

It doesn't simply seem to be decreasing after crossing a certain threshold, either. However, it doesn't drop to "critical" levels.